So one of my symptoms is yellow semen. I had a semen test back in February when I told you that I went to the urologist and he said all good . Now I checked every parameter on healthline dot com and that’s what I found . My sperm diagram : Days of abstention: 6 , Semen volume :3.6 ml range ( 1.5-6), Ph :8 ( range 7.2 -7.8 ) -> more than 7.8 shows that there is an infection , Liquidation: 40 minutes , View: translucent , Number of sperms /ml : 35.5 million per ml ~>pretty low , Total number : 128 million , Leukocytes: 1-2 -> Normal is less than 1 . This could show pyospermia , Motility the first hour : active 50% , medium : 30%, not moving : 20%, In blood , also CRP was high 1.88 mg/l SGPT high , 57 U/L I also did a semen and urine culture which were negative . But there are many indicators that there is something wrong . This could be an infection or pyospermia which are causing yellow semen . If you check this website www.invitra.com/en/analysis-of-the-amount-of-leukocytes-in-semen-and-sperm-culture/amp/ it says which could be the causes of of pyospermia and E. Coli as well other bacteria could be present . In conclusion, when lastround made the post about sibo recovery, I didn’t even test for it , I went to the pharmacy and bought the antibiotics and used them for ten days without success. The thing is that it’s not only sibo , I don’t know how could an infection happen with ssris but I think it could be an infection in the genital organs . Either way it is treated with antibiotics. Regarding flexstar , the website says that the cause of pyospermia could also be autoimmune so this could apply too .
For leukocytospermia / pyospermia: “However, most cases of leukocytospermia result in negative cultures.” Source: https://www.ivi-rmainnovation.com/everything-you-need-to-know-about-leukocytospermia/
Treatment: https://www.sciencedirect.com/science/article/pii/S2666334121000015

acute kidney injury is character deterioration in kidney function and manifested by an increase in serum creatinine level with or without reduced urine output so here we have the left and right kidney the renal artery supplies the kidneys the renal artery branches and supplies the functional units of the kidneys called the nephrons now the branches of the renal artery's form what's called the glomerulus which filters the filtrate into the many nephron tubules substances in the filtrate can be reabsorbed and many things secreted into the tubules along its way the end product is urine if we zoom into the area here where the glomerulus is and the tubules the girl merliss is where filtration occurs the afferent arteriole brings blood into the glomerulus filtration occurs and then leaves via the efferent arterioles the efferent arteriole continues to form the Vasa recta between the two Buell and the Vasa recta is the interstitial using this diagram we can appreciate the nephrons for functions for making urine the first is filtration the glomerulus filters your blood reabsorption and then secretion where the two Buell returns needed substances into your blood and removes waste along the tubules and the fourth one is excretion the final product really being urine acute kidney injury is a rapid decrease in glomerular filtration that result in abnormal fluid and electrolyte balance and hazard tamiya as a team you are being an increase in the wastes nitrogen as well as creatinine essentially acute kidney injury can be thought of disruption in the four functions of the nephrons we just talked about clinically acute kidney injury is diagnosed when there is an abrupt increase in serum creatinine Crowden comes from the metabolism of creatine in skeletal muscle and dietary meat intake creatinine is freely filtered across the glomerular and not reabsorbed from the tubules creatinine however can be secreted into the tubules the screening levels are maintained in serum when you have acute kidney injury the four functions of making urine are disrupted and so you have an increase in the waste that is creatinine the main fact is affecting the actual glomerular filtration our hydrostatic pressure which is your blood pressure essentially and the colloid osmotic pressure and the fluid pressure which are going the other way the net filtration pressure favors going into the tubules in acute kidney injury you have reduced glomerular filtration which can be due to a number of things firstly a reduced hydrostatic pressure which is your blood pressure or cumulative increase in the colloid osmotic pressure or fluid pressure from whatever cause as a result of these changes you have a accumulation of creatinine in serum creatinine does not get filtered by the glomerulus or secreted into the tubules resulting in elevated serum creatinine to make it simple the causes of acute renal injury or kidney injury can be classified into three types these are pre rino which is as a result of decreased perfusion to the normal kidney in torino acute kidney injury and post renal also called post obstructive acute kidney injury pree renal acute kidney injury is also known as pre renal azerty mia pre renal causes include hypovolemia reduced cardiac output like in cardiogenic shock for example or reduced effective circulatory volume such as in congestive heart failure or liver failure essentially these causes lead to reduced blood flow to the kidneys and so you have a reduced hydrostatic pressure thus you get reduced glomerular filtration another cause of pre renal acute kidney injury is impaired renal autoregulation due to our the use of neurotoxins such as non-steroidal anti-inflammatory drugs now non-steroidal anti-inflammatory drugs they actually cause vasoconstriction to the afferent arterioles and so this will result in reduced hydrostatic pressure resulting in reduced glomerular filtration ACE inhibitors or angiotensin receptor blockers causes vasodilation of the efferent arterioles which is useful at times but in renal injury it actually amplifies the renal injury because it reduces the hydrostatic pressure and reduces glomerular filtration rate finally cyclosporine also causes acute kidney injury now my definition the pre renal acute kidney injury we talked about doesn't actually involve the parenchyma doesn't involve the in actual nephrons really so pre rino acute kidney injury is usually reversible however prolonged pre renal can lead to ischemic injury causing injury no acute kidney injury and we'll talk about intra renal acute kidney injury later but first let's talk about post renal causes of acute kidney injury post renal acute kidney injury is also known as post obstructive acute kidney injury and it's essentially obstruction anywhere along the urinary tract from the renal pelvis ureter bladder to the urethra it can be caused by renal stones which can cause obstruction along the ureter this leads to Dalit ation of the ureter proximally termed hydronephrosis other causes of post renal include prostate enlargement prostate cancer cervical cancer bladder cancer which causes all obstruction and finally here I wrote a lower urinary tract infection which is kind of controversial because technically it doesn't but if it goes up to your kidneys it can and so post renal causes can lead to internal causes of acute kidney injury because as obstruction or infection occurs it can be pushed up the urine can be pushed up the waist pushed up causing injury to the nephrons increasing serum creatinine you intra renal causes of acute kidney injury are probably the most important to understand but essentially it can be divided to four types intra renal causes include glomerular nephritis tubular disease interstitial disease and vascular disease so for glomerulonephritis it is essentially inflammation of the glomerulus the proper term for this is nephrotic syndrome and there are many causes of it the second group of intra renal causes is tubular disease the most important is acute tubular necrosis which is a result of prolonged ischemia from pre renal acute kidney injury and is probably the most common renal injury in hospitals other tubular disease can be from infection injuring the tubular cells or from nephrotoxic the third group of intra renal causes are the interstitial disease these include acute interstitial nephritis and acute interstitial nephritis can also be from a number of things ischemia infection connective tissue diseases as well as the use of nephrotoxic or nefra toxins the last group of internal causes as vascular which includes vasculitis and microangiopathic hemolytic anemia causes such as TTP and hates us now we can appreciate the pathophysiology which occurs in intra renal acute kidney injury by focusing on the changes that occur in this diagram with prolonged pre renal acute kidney injury or Aki for short this can lead to ischemia which leads to tubular disease with tubular injury the injured tubular cells form epithelial castes epithelial castes occurs from damaged tubules and can be seen on urine microscopy this will result in an inflammatory reaction whereby there is an increase in adhesion molecules and leukocyte activation neutrophils are recruited to the area and further perpetuate the inflammatory response injuring the tubules this causes further damage to the tubules and surrounding areas including the interstitial leukocytes form white cell casts which can be seen in urine microscopy and signifies inflammation or infection inflamed interstitial from whatever cause including infection or Nefer toxins also result in an inflammatory response leading to leukocyte recruitment tubular injury and white cell casts in glomerulonephritis there is inflammation of the glomerulus this is special because with damaged glomerulus the red blood cells can actually pass through as filtrate and the red blood cells can form casts again these red blood cell casts can be seen in urine microscopy and signifies glomerular injury lamella information as well as vascular inflammation promotes the inflammatory response as we discussed earlier in in Torino Aki the inflammatory response results in the release of many peptides involved in vasoconstriction this is why in Torino Aki usually coexists with pre reno aki due to vasoconstriction when the kidneys are in this period of reduced blood flow they are vulnerable to further insult with Nefer toxins such as non-steroidal anti-inflammatory drugs or amino glycosides some Nefer toxins can also directly actually injure the tubules or the interstitial important effort options to know about include non-steroidal anti-inflammatory drugs I donated contrast amino glycosides myoglobin crystals formed in those in your body as well as in myeloma where you have power proteins four investigations in acute kidney injury baseline blood tests are important and this includes full blood count Electra la urea creatinine you will have an elevation of creatinine which is diagnostic for Aki you may have an elevation in urea as well as nitrogen for pre renal the fractional excretion of sodium and urea can be calculated and is helpful in diagnosing or differentiating pre renal to acute tubular necrosis for example also with pre renal it's important to investigate or look out look out for the fluid state of the patient if there are hypovolemic or hypervolemic intra renal investigations of acute kidney injury include urinalysis urine MCs microscopic culture sensitivity urine casts which we talked about the different types of casts renal ultrasound urine protein creatine ratio and albumin [ __ ] ratio for post renal causes it's again important to do a urinalysis and urine MCs but here fundamentally doing a bladder scan is easy to check for essentially urine retention you can check it the catheter if the patient has one see if it's blocked or kinked because this can cause post renal Aki also imaging is actually very important so Ct KUB or even a renal tract ultrasound is useful to check for any obstruction signs management of Aki will depend on the course but essentially give someone fluids if it's a pre renal cause and they're hypovolemic or diuretics if they're fluid overloaded to help clear the fluid stop never toxins we talked about earlier treat the underlying cause again if it's an infection use antibiotics if it's renal stone treat the pain but also try to remove the stone if it's big if it's an obstructed catheter try flushing it treat underlying complications of acute kidney injury mainly electrolyte imbalances some of these complications can get out of hand and so some patients will require dialysis so indications for acute dialysis in scenario where someone has acute kidney injury you can easily remember with the acronym AEIOU so a is for acidosis which is refractory it doesn't change is for electrolyte imbalance specifically refractory severe hyperkalemia intoxication or ingestion you can remember what as the acronym slime so these toxins include silicic acid too much lithium isopropanol magnesium laxatives ethylene glycol oh is for overload so fluid overload just as persistent and you is for uremic complications because with acute kidney injury as well as chronic and injury urea can be so high and can lead to complications such as pericarditis as well as platelet dysfunction leading to bleeding and these are some indications for acute dialysis to remove all this waste from the blood thank you for watching I hope you enjoyed this video you

Other discussions
Episode 1 - Pneumococcus
Episode 2 - Scrape wound
Episode 3 - Influenza
Episode 4 - Food poisoning
Episode 5 - Cedar pollen allergy
Episode 6 - Erythroblasts and myelocytes
Episode 7 - Cancer
Episode 8 - Blood circulation
Episode 9 - Thymocytes
Episode 10 - Staphylococcus Aureus
Episode 11 - Heat shock
Episodes 12+13 - Hemorrhagic shock

Background

Hello again! I am a medical doctor currently in residency training in the field of pathology. It's my job to study and categorize all sorts of human disease, usually by studying the effect it has on the human body and particularly its cells. Hataraku Saibou is a series written by Akane Shimizu featuring anthropomorphized human cells battling such disease. The creators seem to have a strong penchant for both accuracy and subtle detail, so I am here to help provide an explanation of and background information for each episode so you won't miss anything obscure. Call me Dr. Eightball. Spoilers follow!
I need to address a pretty major error from my last week's analysis, regarding the role of macrophages in erythropoiesis (formation of red blood cells). It seems they play a quite large and central role, both in terms of maintaining the CD45+ hematopoietic stem cell population, anchoring the erythroid colonies, and providing iron to the growing red blood cells. For those curious about the complex relationship between the red blood cell and the macrophage, I recommend this nearly comprehensive (and free) review article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5288342/pdf/fimmu-08-00073.pdf Plus, it's got a cool name.
Another major correction: I accidentally said that the hematopoietic stem cells that give rise to myeloid cells are CD45+; that should be CD34+.
Finally! My favorite topic, neoplasia. As a pathologist in training I probably spend a quarter or more of my time identifying and categorizing tumors, of which there are thousands described, involving virtually any type of nucleated cells--liver cells, neurons, sweat glands, lymphatic endothelium, you name it. Before we get too far into the episode, I want to define a few important terms, and try to explain what cancer actually is...
Cancer is an uncontrolled, unregulated growth of cells that results usually from a genetic aberration. To throw around the phrase "cancer" implies that this growth is capable of metastatic spread, that is, can seed foreign sites in the body. Another word for this is a malignant tumor. Not all tumors, or neoplasia, will behave in a malignant fashion. Benign tumors, due to various nuances of their underlying biology, do not cause metastatic disease, but they are still monoclonal, meaning every cell is genetically identical and arose from a single "patient zero" mutated cell. "Hold on, aren't all of your cells genetically identical?" Normally, yes, but all cells can acquire somatic mutations from things like mutagens, replication errors, and viral infections. Cancers can range in lethality from insignificant (a low-grade prostate cancer that is best monitored but otherwise left alone) to immediately deadly (an infiltrative brain tumor or pancreatic tumor that kills in weeks after diagnosis). Their treatment is another topic altogether, I can go into more depth there if people are interested.

Character Highlight

https://preview.redd.it/edg3e279uch11.png?width=1000&format=png&auto=webp&s=7e6be12648b13234112d25928d214043b5e27f07
Natural Killer (NK) Cell
The natural killer cell! What an intimidating name, but an appropriate one. NK cells are very similar in appearance and function to the cytotoxic T-cells. Their chief role is to cause cytotoxicity, able to destroy both human and foreign cells using a variety of weapons, such as perforins and granzymes, which literally punch holes in target membranes.
So how should they be distinguished from cytotoxic T-cells? NK cells are more effective at destroying tumoral cells. While both cells can recognize abnormal protein antigens that are presented on the HLA molecules of tumor cells, the NK cell is furthermore capable of recognizing when the expression of the HLA itself is abnormal (as it is often decreased in tumor cells). They are also sensitive to danger signals and molecules that are over-expressed in cancerous transformation (PVR, Nectin-2). NK cells are also excellent at killing cancer stem cells, a highly malignant subpopulation that helps regenerate the tumor cell population. Finally, NK cells have the means by which to locally orchestrate immune responses, signaling to T and B lymphocytes.
These are actually neoplastic NK cells, but the morphology still applies.
Tumor cells have some ways to get around NK cell surveillance, however. By upregulating or downregulating certain signaling molecules, some can achieve “immune stealth”, going unnoticed by the immune system during their critical early phases. One can think of our immune system as providing a selective pressure towards this stealth, as any tumor that is detected otherwise is promptly destroyed. It is not really clear to me how often tumorigenesis occurs but is quashed by your immune system before coming to clinical attention, but it is definitely true that the role is significant, as immunocompromised patients are more prone to developing cancers from multiple causes.
In addition to killing tumor cells, NK cells will also kill any macrophages or other cells that have been shown to sometimes promote tumor growth. So don't cross her. There are currently millions (probably billions) of dollars in research right now developing means by which to reprogram/supercharge/otherwise administer NK cells that are specific towards tumors as a new form of clinical therapy.
A fun and cruel irony is that as any nucleated cell is capable of becoming neoplastic, NK cells themselves can become cancerous (see: EBV-related NK proliferative diseases, extranodal NK/T-cell lymphoma, etc). I don’t think we’re going to get that far in depth though, as the cancer featured in this episode is not even named.

Episode 6.5 - Cancer cell pt 1

If you missed last week: Since this is a 1.5 episode arc I figured I would do it all in one go. So we are actually going back to episode 6 to start the analysis.
15:30 - I wonder why U-1146 is always sipping green tea...or what that could be an allusion to. Immune cells mostly use the same cellular fuels as every other cell, namely simple sugars, ketone bodies, fatty acids, etc.
15:40 - Very interesting, bizarre-appearing cell. It seems pretty reasonable for cancer cells to look awful, as cancers have abnormal looking architecture and cytomorphology as they acquire more mutations. Check out this example:
Left: Normal thyroid, with follicular cells forming relatively neat rings. Right: Anaplastic thyroid carcinoma, with extreme aberrations in cell size and appearance.
16:00 - Neutrophils should not be fighting cancer cells, as they would have no way to recognize that the cell is abnormal. An exception to this is when the tumor has grown so large that it outstrips its vascular supply and starts to necrose, spilling pro-inflammatory contents which the neutrophil could then respond to. Neutrophils are actually thought in a lot of cases to promote tumor formation, but research in this is ongoing.
17:00 - Intro to NK cell! I'm unsure what is with her competitive/adversarial dynamic with cytotoxic (CD8+) T-lymphocyte. They serve in a lot of similar roles, but as discussed above, she's a bit better at recognizing tumor cells, and also can orchestrate a T-lymphocyte response (I am unsure if the reverse applies, however). I could reasonably envision that they are capable of killing each other, though that would probably be inappropriate...
20:20 - Since this show focuses so heavily on the immune cells, we don't get to learn a lot about all of the other epithelial and stromal cells that make up organs, or the body more generally. It would be more interesting if this derelict complex were characterized as a particular organ...
21:00 - A rejection reaction, lol. That's pretty good. Cytotoxic T-lymphocytes are one of the main cells responsible for organ rejection in transplants (B-cells play a role as well). In fact, if we find a collection of them in eg an endomyocardial biopsy, we will call our clinicians who will immediately begin pulse-dosing steroids. "Compatibility" usually refers to antigens like the Human Leukocyte Antigens (HLA, or Major Histocompatibility Complex) that determine whether rejection will occur.

Episode 7 - Cancer cell pt 2

1:40 – Dunno. Is shoelace breakage really a bad omen in Japan?
2:35 – Cancers, at least in their early stages, will generally resemble whatever cell lineage they arise from (well-differentiated), though their behavior will generally belie their neoplastic origin. As cancers mutate, they accrue more and more errors and abnormalities (as the normal mechanisms by which a cell would apoptose, or kill itself, are no longer being triggered).
3:05 – I should touch on what causes cancers to form a bit more. They almost all arise from genetic abnormalities, but the specifics can be varied and very important. Some may form because a growth signal system is mutated to always be “on”. Some form because a suicide pathway is permanently disabled. Any abnormality that leads to dysregulation of growth can form a cancer.
4:15 – I’m not really familiar with cancer cells “attacking” immune cells, as they would generally not have the sort of complex machinery needed to do this. Most of their adaptations pertain to resisting and avoiding immune cells.
5:15 – Ooh, see that diagram on the bottom right of the board? Those are the phases of mitosis, the process by which a cell divides.
10:00 - Let me elaborate a bit more on what I described earlier. As tumor cells grow, they require a constant influx of oxygen and nutrients to support their multiplication. As they begin to outstrip the local tissue infrastructure, they will promote formation of new blood vessels (angiogenesis) to support their growth. Drugs that block this signaling are approved for the treatment of certain cancers (eg. Bevacizumab in colorectal cancers). Remember, the red cells can't know any better! This very energy-demanding process often causes the patient to experience unintentional weight loss and cachexia.
11:30 - I've got nothing to say about the backstory here, but more on tumorigenesis: We talked about what the mutations can cause, but what causes the mutations? You've all heard of the effects of mutagens like radiation, smoking, and more exotic stuff like aflatoxins/vinyl chlorides/etc. Mutations also can occur as a result of copying errors--consider that the polymerase enzymes that encode DNA have to copy all 3 billion base pairs every time the cell divides. This process is not perfect, and errors do occur. Cells have ways of recognizing and correcting these errors, but they don't work every time. We can also look at oncogenic infections, where viruses integrate into or otherwise disrupt DNA. Epstein-Barr Virus (EBV or HHV5, the virus that causes infectious mono) is famous for this. Kaposi's sarcoma is caused by another member of the herpesvirus family (HHV8).
12:00 - I do not know how many "cancer cells" form on a regular basis. This number is probably derived from mathematical models as it can be almost impossible for modern scientific methods to distinguish individual tumor cells from normal somatic cells in a living organism. I'd love if someone had a source though, I can't find one.
13:00 - Why, exactly, are cancers dangerous? Metastatic spread will eventually disrupt the normal function of whatever tissues they invade. Mass effect can cause symptoms (see: a tumor compressing nerves, vessels, or ducts), and tumors can cause edema (very dangerous in the brain), malignant effusions, etc. Chunks of tumor that break off in circulation can cause embolism. The list goes on.
14:00 - This macrophage doesn't seem phased...I wonder if she is a tumor-associated macrophage (TAM), which promotes tumorigenesis.
15:00 - ok nvm lol
15:20 - This united front of all immune cells vs tumor is very dramatic and fun, but not very realistic.
17:40 - This...is a stretch. I did a literature search and found a handful of Japanese research articles that looked at the effect of laughter on NK cell activity in multiple diseases, but they tended to be low-power and more generally low-quality studies. Not saying it's pure bullshit, but since this is not something that can be uniformly characterized and administered, there is not much in the literature about it. Looks like the article is not hidden behind a paywall, so take a look.
18:10 - A note from the manga: Cancer-boy says "Gaan", which sounds like an expression of dismay but also means "Crab"...appropriate considering what the zodiac symbol for Cancer is.
21:30 - Red cells can't summon an immune response! But we've already established our two heroes are exceptional, right?

Summary

A neoplastic growth that was able to be resolved without any clinical intervention. This does happen on at least a semi-regular basis. Usually, once a tumor reaches a critical size threshold (maybe 1cm or so), they rarely resolve on their own, and will grow until they manifest clinical symptoms, at which point they must be treated. Surgical resection can be simple, and curative in organ-confined disease. If the cancer has already spread, then surgery theoretically cannot be curative. Then we have an array of chemotherapeutics and radiation treatments, ranging from the old and barbaric (metabolic toxins that kill cancers cells on the basis of their high metabolism...but also poison the rest of you) to the cutting edge and laser-precise (small molecules that specifically target mutated proteins). If anyone is interested in the concept of personalized medicine, I'd be glad to talk about it more. But we're getting a little off track now.
Courtesy NEJM.org; Croce, Carlo M. \"Oncogenes and cancer.\" New England Journal of Medicine 358.5 (2008): 502-511.
This was a fun one. If we see cancer again in the future, I would love for them to be distinguished a bit more. After all, the field of oncology is enormous, with thousands of different cancers all with different behaviors and appearances. They are about as varied as bacteria and viruses! But I'll take my neoplastic fix for now. Hope you all enjoyed it!

References

Sungur, Can M., and William J. Murphy. "Positive and negative regulation by NK cells in cancer." Critical Reviews™ in Oncogenesis 19.1-2 (2014).
Bellora, Francesca, et al. "Human NK cells and NK receptors." Immunology letters 161.2 (2014): 168-173.
Hayashi, Takashi, et al. "Laughter up-regulates the genes related to NK cell activity in diabetes." Biomedical Research28.6 (2007): 281-285.

From Wikipedia, the free encyclopedia Jump to navigationJump to search This article is about the cat species that is commonly kept as a pet. For the cat family, see Felidae. For other uses, see Cat (disambiguation) and Cats (disambiguation). For technical reasons, "Cat #1" redirects here. For the album, see Cat 1 (album). Domestic cat[1] Cat poster 1.jpg Various types of domestic cat Conservation status Domesticated Scientific classification e Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Suborder: Feliformia Family: Felidae Subfamily: Felinae Genus: Felis Species: F. silvestris Subspecies: F. s. catus Trinomial name Felis silvestris catus Linnaeus, 1758[2] Synonyms Felis catus (original combination)[3] Felis catus domestica (invalid junior synonym)[4]
The domestic cat (Felis silvestris catus or Felis catus)[1][5] is a small, typically furry, carnivorous mammal. They are often called house cats[6] when kept as indoor pets or simply cats when there is no need to distinguish them from other felids and felines. They are often valued by humans for companionship and for their ability to hunt vermin. There are more than seventy cat breeds recognized by various cat registries.
Cats are similar in anatomy to the other felids, with a strong flexible body, quick reflexes, sharp retractable claws and teeth adapted to killing small prey. Cat senses fit a crepuscular and predatory ecological niche. Cats can hear sounds too faint or too high in frequency for human ears, such as those made by mice and other small animals. They can see in near darkness. Like most other mammals, cats have poorer color vision and a better sense of smell than humans. Cats, despite being solitary hunters, are a social species, and cat communication includes the use of a variety of vocalizations (mewing, purring, trilling, hissing, growling and grunting) as well as cat pheromones and types of cat-specific body language.[7]
Cats have a high breeding rate.[8] Under controlled breeding, they can be bred and shown as registered pedigree pets, a hobby known as cat fancy. Failure to control the breeding of pet cats by spaying and neutering, as well as the abandonment of former household pets, has resulted in large numbers of feral cats worldwide, requiring population control.[9] In certain areas outside cats' native range, this has contributed, along with habitat destruction and other factors, to the extinction of many bird species. Cats have been known to extirpate a bird species within specific regions and may have contributed to the extinction of isolated island populations.[10] Cats are thought to be primarily responsible for the extinction of 87 species of birds,[11] and the presence of feral and free-ranging cats makes some otherwise suitable locations unsuitable for attempted species reintroduction.[12]
Because cats were venerated in ancient Egypt, they were commonly believed to have been domesticated there,[13] but there may have been instances of domestication as early as the Neolithic from around 9,500 years ago (7500 BC).[14] A genetic study in 2007[15] concluded that all domestic cats are descended from Near Eastern wildcats, having diverged around 8000 BC in the Middle East.[13][16] A 2016 study found that leopard cats were undergoing domestication independently in China around 5500 BC, though this line of partially domesticated cats leaves no trace in the domesticated populations of today.[17][18] A 2017 study confirmed that domestic cats are descendants of those first domesticated by farmers in the Near East around 9,000 years ago.[19][20]
As of a 2007 study, cats are the second-most popular pet in the U.S. by number of pets owned, behind freshwater fish.[21] In a 2010 study, they were ranked the third-most popular pet in the UK, after fish and dogs, with around 8 million being owned.[22]
Contents 1 Taxonomy and evolution 2 Nomenclature and etymology 3 Biology 3.1 Anatomy 3.2 Physiology 3.2.1 Nutrition 3.3 Senses 3.4 Health 3.4.1 Diseases 3.5 Genetics 4 Behavior 4.1 Sociability 4.2 Communication 4.3 Grooming 4.4 Fighting 4.5 Hunting and feeding 4.6 Running 4.7 Play 4.8 Reproduction 5 Ecology 5.1 Habitats 5.2 Feral cats 5.3 Impact on prey species 5.4 Impact on birds 6 Interaction with humans 6.1 Cat show 6.2 Cat café 6.3 Ailurophobia 6.4 Cat bites 6.5 Infections transmitted from cats to humans 6.6 History and mythology 6.6.1 Superstitions and cat burning 7 See also 8 Notes 9 References 10 External links Taxonomy and evolution Main article: Cat evolution The domestic cat is a member of the cat family, the felids, which are a rapidly evolving family of mammals that share a common ancestor only 10–15 million years ago[23] and include lions, tigers, cougars and many others. Within this family, domestic cats (Felis catus) are part of the genus Felis, which is a group of small cats containing about seven species (depending upon classification scheme).[1][24] Members of the genus are found worldwide and include the jungle cat (Felis chaus) of southeast Asia, European wildcat (F. silvestris silvestris), African wildcat (F. s. lybica), the Chinese mountain cat (F. bieti), and the Arabian sand cat (F. margarita), among others.[25]
The domestic cat is believed to have evolved from the Near Eastern wildcat, whose range covers vast portions of the Middle East westward to the Atlantic coast of Africa.[26][27] Between 70,000 and 100,000 years ago the animal gave rise to the genetic lineage that eventually produced all domesticated cats,[28] having diverged from the Near Eastern wildcat around 8,000 BC in the Middle East.[13][16]
The domestic cat was first classified as Felis catus by Carl Linnaeus in the 10th edition of his Systema Naturae published in 1758.[1][2] Because of modern phylogenetics, domestic cats are usually regarded as another subspecies of the wildcat, F. silvestris.[1][29][30] This has resulted in mixed usage of the terms, as the domestic cat can be called by its subspecies name, Felis silvestris catus.[1][29][30] Wildcats have also been referred to as various subspecies of F. catus,[30] but in 2003, the International Commission on Zoological Nomenclature fixed the name for wildcats as F. silvestris.[31] The most common name in use for the domestic cat remains F. catus. Sometimes, the domestic cat has been called Felis domesticus[32] as proposed by German naturalist J. C. P. Erxleben in 1777,[33] but these are not valid taxonomic names and have been used only rarely in scientific literature.[34] A population of Transcaucasian black feral cats was once classified as Felis daemon (Satunin 1904) but now this population is considered to be a part of the domestic cat.[35]
All the cats in this genus share a common ancestor that is believed to have lived around 6–7 million years ago in the Near East (the Middle East).[36] The exact relationships within the Felidae are close but still uncertain,[37][38] e.g. the Chinese mountain cat is sometimes classified (under the name Felis silvestris bieti) as a subspecies of the wildcat, like the North African variety F. s. lybica.[29][37]
Ancient Egyptian sculpture of the cat goddess Bastet. The earliest evidence of felines as Egyptian deities comes from c. 3100 BC. In comparison to dogs, cats have not undergone major changes during the domestication process, as the form and behavior of the domestic cat is not radically different from those of wildcats and domestic cats are perfectly capable of surviving in the wild.[39][40] Fully domesticated house cats often interbreed with feral F. catus populations,[41] producing hybrids such as the Kellas cat. This limited evolution during domestication means that hybridisation can occur with many other felids, notably the Asian leopard cat.[42] Several natural behaviors and characteristics of wildcats may have predisposed them for domestication as pets.[40] These traits include their small size, social nature, obvious body language, love of play and relatively high intelligence.[43]:12–17 Several small felid species may have an inborn tendency towards tameness.[40]
Cats have either a mutualistic or commensal relationship with humans. Two main theories are given about how cats were domesticated. In one, people deliberately tamed cats in a process of artificial selection as they were useful predators of vermin.[44] This has been criticized as implausible, because the reward for such an effort may have been too little; cats generally do not carry out commands and although they do eat rodents, other species such as ferrets or terriers may be better at controlling these pests.[29] The alternative idea is that cats were simply tolerated by people and gradually diverged from their wild relatives through natural selection, as they adapted to hunting the vermin found around humans in towns and villages.[29]
Nomenclature and etymology The origin of the English word cat (Old English catt) and its counterparts in other Germanic languages (such as German Katze), descended from Proto-Germanic *kattōn-, is controversial. It has traditionally thought to be a borrowing from Late Latin cattus, 'domestic cat', from catta (used around 75 AD by Martial),[45][46] compare also Byzantine Greek κάττα, Portuguese and Spanish gato, French chat, Maltese qattus, Lithuanian katė, and Old Church Slavonic kotъ (kotka), among others.[47] The Late Latin word is generally thought to originate from an Afro-Asiatic language, but every proposed source word has presented problems. Many references refer to "Berber" (Kabyle) kaddîska, 'wildcat', and Nubian kadīs as possible sources or cognates, but M. Lionel Bender suggesets the Nubian term is a loan from Arabic قِطَّة qiṭṭa.[48] Jean-Paul Savignac suggests the Latin word is from an Ancient Egyptian precursor of Coptic ϣⲁⲩ šau, 'tomcat', or its feminine form suffixed with -t,[49] but John Huehnergard says "the source [...] was clearly not Egyptian itself, where no analogous form is attested."[48] Huehnergard opines it is "equally likely that the forms might derive from an ancient Germanic word, imported into Latin and thence to Greek and to Syriac and Arabic". Guus Kroonen also considers the word to be native to Germanic (due to morphological alternations) and Northern Europe, and suggests that it might ultimately be borrowed from Uralic, cf. Northern Sami gađfe, 'female stoat', and Hungarian hölgy, 'stoat'; from Proto-Uralic *käďwä, 'female (of a furred animal)'.[50] In any case, cat is a classic example of a Wanderwort.
An alternative word is English puss (extended as pussy and pussycat). Attested only from the 16th century, it may have been introduced from Dutch poes or from Low German puuskatte, related to Swedish kattepus, or Norwegian pus, pusekatt. Similar forms exist in Lithuanian puižė and Irish puisín or puiscín. The etymology of this word is unknown, but it may have simply arisen from a sound used to attract a cat.[51][52]
A group of cats can be referred to as a clowder or a glaring;[53] a male cat is called a tom or tomcat[54] (or a gib,[55] if neutered); an unspayed female is called a queen,[56] especially in a cat-breeding context; and a juvenile cat is referred to as a kitten. The male progenitor of a cat, especially a pedigreed cat, is its sire,[57] and its mother is its dam[58] In Early Modern English, the word kitten was interchangeable with the now obsolete word catling.[59]
A pedigreed cat is one whose ancestry is recorded by a cat fancier organization. A purebred (or pure-bred) cat is one whose ancestry contains only individuals of the same breed. Many pedigreed and especially purebred cats are exhibited as show cats. Cats of unrecorded, mixed ancestry are referred to as domestic short-haired or domestic long-haired cats (by coat type), or commonly as random-bred, moggies (chiefly British), or (using terms borrowed from dog breeding) mongrels or mutt-cats.
While the African wildcat is the ancestral subspecies from which domestic cats are descended, and wildcats and domestic cats can completely interbreed (being subspecies of the same species), several intermediate stages occur between domestic pet and pedigree cats on one hand and entirely wild animals on the other. The semi-feral cat, a mostly outdoor cat, is not owned by any one individual, but is generally friendly to people and may be fed by several households. Truly feral cats are associated with human habitation areas, foraging for food and sometimes intermittently fed by people, but are typically wary of human interaction.[41]
Biology Anatomy Main article: Cat anatomy
Diagram of the general anatomy of a male Domestic cats are similar in size to the other members of the genus Felis, typically weighing between 4 and 5 kg (9 and 10 lb).[37] Some breeds, such as the Maine Coon, can occasionally exceed 11 kg (24 lb). Conversely, very small cats, less than 2 kg (4 lb), have been reported.[60] The world record for the largest cat is 21 kg (50 lb).[61][self-published source] The smallest adult cat ever officially recorded weighed around 1 kg (2 lb).[61] Feral cats tend to be lighter, as they have more limited access to food than house cats. The Boston Cat Hospital weighted trapped feral cats, and found the average feral adult male to weigh 4 kg (9 lb), and average adult female 3 kg (7 lb).[62] Cats average about 23–25 cm (9–10 in) in height and 46 cm (18 in) in head/body length (males being larger than females), with tails averaging 30 cm (12 in) in length;[63] feral cats may be smaller on average.
Cats have seven cervical vertebrae, as do almost all mammals; 13 thoracic vertebrae (humans have 12); seven lumbar vertebrae (humans have five); three sacral vertebrae like most mammals (humans have five); and a variable number of caudal vertebrae in the tail (humans have only vestigial caudal vertebrae, fused into an internal coccyx).[64]:11 The extra lumbar and thoracic vertebrae account for the cat's spinal mobility and flexibility. Attached to the spine are 13 ribs, the shoulder, and the pelvis.[64] :16 Unlike human arms, cat forelimbs are attached to the shoulder by free-floating clavicle bones which allow them to pass their body through any space into which they can fit their head.[65]
Cat skull The cat skull is unusual among mammals in having very large eye sockets and a powerful and specialized jaw.[66]:35 Within the jaw, cats have teeth adapted for killing prey and tearing meat. When it overpowers its prey, a cat delivers a lethal neck bite with its two long canine teeth, inserting them between two of the prey's vertebrae and severing its spinal cord, causing irreversible paralysis and death.[67] Compared to other felines, domestic cats have narrowly spaced canine teeth, which is an adaptation to their preferred prey of small rodents, which have small vertebrae.[67] The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently shears meat into small pieces, like a pair of scissors. These are vital in feeding, since cats' small molars cannot chew food effectively, and cats are largely incapable of mastication.[66]:37 Although cats tend to have better teeth than most humans, with decay generally less likely because of a thicker protective layer of enamel, a less damaging saliva, less retention of food particles between teeth, and a diet mostly devoid of sugar, they are nonetheless subject to occasional tooth loss and infection.[68]
Cats, like dogs, are digitigrades. They walk directly on their toes, with the bones of their feet making up the lower part of the visible leg.[69] Cats are capable of walking very precisely because, like all felines, they directly register; that is, they place each hind paw (almost) directly in the print of the corresponding fore paw, minimizing noise and visible tracks. This also provides sure footing for their hind paws when they navigate rough terrain. Unlike most mammals, when cats walk, they use a "pacing" gait; that is, they move the two legs on one side of the body before the legs on the other side. This trait is shared with camels and giraffes. As a walk speeds up into a trot, a cat's gait changes to be a "diagonal" gait, similar to that of most other mammals (and many other land animals, such as lizards): the diagonally opposite hind and fore legs move simultaneously.[70]
Like almost all members of the Felidae, cats have protractable and retractable claws.[71] In their normal, relaxed position, the claws are sheathed with the skin and fur around the paw's toe pads. This keeps the claws sharp by preventing wear from contact with the ground and allows the silent stalking of prey. The claws on the fore feet are typically sharper than those on the hind feet.[72] Cats can voluntarily extend their claws on one or more paws. They may extend their claws in hunting or self-defense, climbing, kneading, or for extra traction on soft surfaces. Most cats have five claws on their front paws, and four on their rear paws.[73] The fifth front claw (the dewclaw) is proximal to the other claws. More proximally is a protrusion which appears to be a sixth "finger". This special feature of the front paws, on the inside of the wrists, is the carpal pad, also found on the paws of big cats and dogs. It has no function in normal walking, but is thought to be an antiskidding device used while jumping. Some breeds of cats are prone to polydactyly (extra toes and claws).[73] These are particularly common along the northeast coast of North America.[74]
Physiology Cats are familiar and easily kept animals, and their physiology has been particularly well studied; it generally resembles those of other carnivorous mammals, but displays several unusual features probably attributable to cats' descent from desert-dwelling species.[32] For instance, cats are able to tolerate quite high temperatures: Humans generally start to feel uncomfortable when their skin temperature passes about 38 °C (100 °F), but cats show no discomfort until their skin reaches around 52 °C (126 °F),[66]:46 and can tolerate temperatures of up to 56 °C (133 °F) if they have access to water.[75]
Normal physiological values[76]:330 Body temperature 38.6 °C (101.5 °F) Heart rate 120–140 beats per minute Breathing rate 16–40 breaths per minute
Thermograph of various body parts of a cat Cats conserve heat by reducing the flow of blood to their skin and lose heat by evaporation through their mouths. Cats have minimal ability to sweat, with glands located primarily in their paw pads,[77] and pant for heat relief only at very high temperatures[78] (but may also pant when stressed). A cat's body temperature does not vary throughout the day; this is part of cats' general lack of circadian rhythms and may reflect their tendency to be active both during the day and at night.[79]:1 Cats' feces are comparatively dry and their urine is highly concentrated, both of which are adaptations to allow cats to retain as much water as possible.[32] Their kidneys are so efficient, they can survive on a diet consisting only of meat, with no additional water,[80] and can even rehydrate by drinking seawater.[81][79]:29While domestic cats are able to swim, they are generally reluctant to enter water as it quickly leads to exhaustion.[82]
Nutrition Cats are obligate carnivores: their physiology has evolved to efficiently process meat, and they have difficulty digesting plant matter.[32] In contrast to omnivores such as rats, which only require about 4% protein in their diet, about 20% of a cat's diet must be protein.[32] A cat's gastrointestinal tract is adapted to meat eating, being much shorter than that of omnivores and having low levels of several of the digestive enzymes needed to digest carbohydrates.[83] These traits severely limit the cat's ability to digest and use plant-derived nutrients, as well as certain fatty acids.[83] Despite the cat's meat-oriented physiology, several vegetarian or vegan cat foods have been marketed that are supplemented with chemically synthesized taurine and other nutrients, in attempts to produce a complete diet. However, some of these products still fail to provide all the nutrients cats require,[84] and diets containing no animal products pose the risk of causing severe nutritional deficiencies.[85] However, veterinarians in the United States have expressed concern that many domestic cats are overfed.[86]
Cats do eat grass occasionally. A proposed explanation is that cats use grass as a source of folic acid. Another is that it is used to supply dietary fiber, helping the cat defecate more easily and expel parasites and other harmful material through feces and vomit.[87]
Cats are unusually dependent on a constant supply of the amino acid arginine, and a diet lacking arginine causes marked weight loss and can be rapidly fatal.[88] Arginine is an essential additive in cat food because cats have low levels of the enzymes aminotransferase and pyrroline-5-carboxylate which are responsible for the synthesis of ornithine and citrulline in the small intestine.[89] Citrulline would typically go on to the kidneys to make arginine, but because cats have a deficiency in the enzymes that make it, citrulline is not produced in adequate quantities to make arginine. Arginine is essential in the urea cycle in order to convert the toxic component ammonia into urea that can then be excreted in the urine. Because of its essential role, deficiency in arginine results in a build up of toxic ammonia and leads to hyperammonemia.[89] The symptoms of hyperammonemia include lethargy, vomiting, ataxia, hyperesthesia and can be serious enough to induce death and coma in a matter of days if a cat is being fed an arginine-free diet. The quick onset of these symptoms is due to the fact that diets devoid in arginine will typically still contain all of the other amino acids, which will continue to be catabolized by the body, producing mass amounts of ammonia that very quickly build up with no way of being excreted.
Another unusual feature is that the cat cannot produce taurine,[note 1] with a deficiency in this nutrient causing macular degeneration, wherein the cat's retina slowly breaks down, causing irreversible blindness.[32] This is due to the hepatic activity of cystinesulfinic acid decarboxylase being low in cats.[91] This limits the ability of cats to biosynthesize the taurine they need from its precursor, the amino acid cysteine, which ultimately results in inadequate taurine production needed for normal function.[91] Deficiencies in taurine result in compensated function of feline cardiovascular and reproductive systems.[91] These abnormalities can also be accompanied by developmental issues in the central nervous system along with degeneration of the retina.[91]
In order to produce the essential vitamin niacin for use in the cat, tryptophan is needed for conversion purposes. However, due to a competing pathway with acetyl coenzyme A (acetyl-CoA), niacin can become deficient and require supplementation.[92] This process occurs when an overactive enzyme, picolinic acid carboxylase, converts the vitamin B6 precursor picolinic acid into the alternate compound acetyl-CoA, instead of converting quinolinate into nictotinic acid mononlucleotide (niacin).[93] Niacin is required in cats as it supports enzyme function. If niacin is deficient in the diet, anorexia, weight loss and an increase in body temperature can result.[94]
Preformed vitamin A is required in the cat for retinal and reproductive health. Vitamin A is considered to be a fat-soluble vitamin and is seen as essential in a cat's diet. Normally, the conversion of beta-carotenes into vitamin A occurs in the intestine (more specifically the mucosal layer) of species, however cats lack the ability to undergo this process.[92] Both the kidney and liver are contributors to the use of vitamin A in the body of the majority of species while the cats liver does not produce the enzyme Beta-carotene 15,15'-monooxygenase which converts the beta-carotene into retinol (vitamin A).[95] To summarize: cats do not have high levels of this enzyme leading to the cleavage and oxidation of carotenoids not taking place.[93]
Vitamin D3 is a dietary requirement for cats as they lack the ability to synthesize vitamin D3 from sunlight.[96] Cats obtain high levels of the enzyme 7-dehydrocholestrol delta 7 reductase which causes immediate conversion of vitamin D3 from sunlight to 7-dehydrocholesterol.[97] This fat soluble vitamin is required in cats for bone formation through the promotion of calcium retention, along with nerve and muscle control through absorption of calcium and phosphorus.[97]
Cats, like all mammals, need to get linoleic acid, an essential fatty acid, from their diet. Most mammals can convert linoleic acid to arachidonic acid, as well as the omega 3 fatty acids (eicosapentaenoic acid and docosahexaenoic acid) through the activity of enzymes, but this process is very limited in cats.[92] The Δ6-desaturase enzyme eventually converts linoleic acid, which is in its salt form linoleate, to arachidonate (salt form of arachidonic acid) in the liver, but this enzyme has very little activity in cats.[92] This means that arachidonic acid is an essential fatty acid for cats as they lack the ability to create required amounts of linoleic acid. Deficiency of arachidonic acid in cats is related to problems in growth, can cause injury and inflammation to skin (e.g. around the mouth) decreased platelet aggregation, fatty liver, increase in birth defects of kittens whose queens were deficient during pregnancy, and reproductive failure in queens.[92] Arachidonic acid can also be metabolized to eicosanoids that create inflammatory responses which are needed to stimulate proper growth and repair mechanisms in the cat.[98]
Cat food § Nutrient chart provides a list of the many nutrients cats require as well as the use of the nutrients in the body and the effects of the deficiency.
Senses Main article: Cat senses
Reflection of camera flash from the tapetum lucidum Cats have excellent night vision and can see at only one-sixth the light level required for human vision.[66]:43 This is partly the result of cat eyes having a tapetum lucidum, which reflects any light that passes through the retina back into the eye, thereby increasing the eye's sensitivity to dim light.[99] Another adaptation to dim light is the large pupils of cats' eyes. Unlike some big cats, such as tigers, domestic cats have slit pupils.[100] These slit pupils can focus bright light without chromatic aberration, and are needed since the domestic cat's pupils are much larger, relative to their eyes, than the pupils of the big cats.[100] At low light levels, a cat's pupils will expand to cover most of the exposed surface of its eyes.[101] However, domestic cats have rather poor color vision and (like most nonprimate mammals) have only two types of cones, optimized for sensitivity to blue and yellowish green; they have limited ability to distinguish between red and green.[102] A 1993 paper reported a response to middle wavelengths from a system other than the rods which might be due to a third type of cone. However, this appears to be an adaptation to low light levels rather than representing true trichromatic vision.[103]
Cats have excellent hearing and can detect an extremely broad range of frequencies. They can hear higher-pitched sounds than either dogs or humans, detecting frequencies from 55 Hz to 79,000 Hz, a range of 10.5 octaves, while humans and dogs both have ranges of about 9 octaves.[104][105] Cats can hear ultrasound, which is important in hunting[106] because many species of rodents make ultrasonic calls.[107] However, they do not communicate using ultrasound like rodents do. Cats' hearing is also sensitive and among the best of any mammal,[104] being most acute in the range of 500 Hz to 32 kHz.[108] This sensitivity is further enhanced by the cat's large movable outer ears (their pinnae), which both amplify sounds and help detect the direction of a noise.[106]
Cats have an acute sense of smell, due in part to their well-developed olfactory bulb and a large surface of olfactory mucosa, about 5.8 cm2 (0.90 in2) in area, which is about twice that of humans.[109] Cats are sensitive to pheromones such as 3-mercapto-3-methylbutan-1-ol,[110] which they use to communicate through urine spraying and marking with scent glands.[111] Many cats also respond strongly to plants that contain nepetalactone, especially catnip, as they can detect that substance at less than one part per billion.[112] About 70–80% of cats are affected by nepetalactone.[113] This response is also produced by other plants, such as silver vine (Actinidia polygama) and the herb valerian; it may be caused by the smell of these plants mimicking a pheromone and stimulating cats' social or sexual behaviors.[114]
Cats have relatively few taste buds compared to humans (470 or so versus more than 9,000 on the human tongue).[115] Domestic and wild cats share a gene mutation that keeps their sweet taste buds from binding to sugary molecules, leaving them with no ability to taste sweetness.[116] Their taste buds instead respond to acids, amino acids like protein, and bitter tastes.[117] Cats and many other animals have a Jacobson's organ in their mouths that is used in the behavioral process of flehmening. It allows them to sense certain aromas in a way that humans cannot. Cats also have a distinct temperature preference for their food, preferring food with a temperature around 38 °C (100 °F) which is similar to that of a fresh kill and routinely rejecting food presented cold or refrigerated (which would signal to the cat that the "prey" item is long dead and therefore possibly toxic or decomposing).[115]
The whiskers of a cat are highly sensitive to touch. To aid with navigation and sensation, cats have dozens of movable whiskers (vibrissae) over their body, especially their faces. These provide information on the width of gaps and on the location of objects in the dark, both by touching objects directly and by sensing air currents; they also trigger protective blink reflexes to protect the eyes from damage.[66]:47
File:BIOASTRONAUTICS RESEARCH Gov.archives.arc.68700.ogv Comparison of cat righting reflexes in gravity versus zero gravity Most breeds of cat have a noted fondness for settling in high places, or perching. In the wild, a higher place may serve as a concealed site from which to hunt; domestic cats may strike prey by pouncing from a perch such as a tree branch, as does a leopard.[118] Another possible explanation is that height gives the cat a better observation point, allowing it to survey its territory. During a fall from a high place, a cat can reflexively twist its body and right itself using its acute sense of balance and flexibility.[119] This is known as the cat righting reflex. An individual cat always rights itself in the same way, provided it has the time to do so, during a fall. The height required for this to occur is around 90 cm (3.0 ft). Cats without a tail (e.g. many specimens of the Manx and Cymric breeds) also have this ability, since a cat mostly relies on leg movement and conservation of angular momentum to set up for landing, and the tail is little used for this feat.[120] Their excellent sense of balance allows cats to move with great stability. A cat falling from heights of up to 3 meters can right itself and land on its paws.[121]
Health Main articles: Cat health and Aging in cats The average lifespan of pet cats has risen in recent years. In the early 1980s, it was about seven years,[122]:33[123] rising to 9.4 years in 1995[122]:33 and 15.1 years in 2018.[124] However, cats have been reported as surviving into their 30s,[125] with the oldest known cat, Creme Puff, dying at a verified age of 38.[126]
Spaying or neutering increases life expectancy: one study found neutered male cats live twice as long as intact males, while spayed female cats live 62% longer than intact females.[122]:35 Having a cat neutered confers health benefits, because castrated males cannot develop testicular cancer, spayed females cannot develop uterine or ovarian cancer, and both have a reduced risk of mammary cancer.[127]
Despite widespread concern about the welfare of free-roaming cats, the lifespans of neutered feral cats in managed colonies compare favorably with those of pet cats.[128]:45[129]:1358 [130][131][132][133]
Diseases Main article: Feline diseases A wide range of health problems may affect cats, including infectious diseases, parasites, injuries, and chronic disease. Vaccinations are available for many of these diseases, and domestic cats are regularly given treatments to eliminate parasites such as worms and fleas.[134]
Genetics Main article: Cat genetics The domesticated cat and its closest wild ancestor are both diploid organisms that possess 38 chromosomes[135] and roughly 20,000 genes.[136] About 250 heritable genetic disorders have been identified in cats, many similar to human inborn errors.[137] The high level of similarity among the metabolism of mammals allows many of these feline diseases to be diagnosed using genetic tests that were originally developed for use in humans, as well as the use of cats as animal models in the study of the human diseases.[138][139]
Behavior See also: Cat behavior and Cat intelligence A black-and-white cat on a fence A cat on a fence Outdoor cats are active both day and night, although they tend to be slightly more active at night.[140][141] The timing of cats' activity is quite flexible and varied, which means house cats may be more active in the morning and evening, as a response to greater human activity at these times.[142] Although they spend the majority of their time in the vicinity of their home, housecats can range many hundreds of meters from this central point, and are known to establish territories that vary considerably in size, in one study ranging from 7 to 28 hectares (17–69 acres).[141]
Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually between 12 and 16 hours, with 13 and 14 being the average. Some cats can sleep as much as 20 hours. The term "cat nap" for a short rest refers to the cat's tendency to fall asleep (lightly) for a brief period. While asleep, cats experience short periods of rapid eye movement sleep often accompanied by muscle twitches, which suggests they are dreaming.[143]
Sociability
Social grooming Although wildcats are solitary, the social behavior of domestic cats is much more variable and ranges from widely dispersed individuals to feral cat colonies that gather around a food source, based on groups of co-operating females.[144][145] Within such groups, one cat is usually dominant over the others.[34] Each cat in a colony holds a distinct territory, with sexually active males having the largest territories, which are about 10 times larger than those of female cats and may overlap with several females' territories.[111] These territories are marked by urine spraying, by rubbing objects at head height with secretions from facial glands, and by defecation.[111] Between these territories are neutral areas where cats watch and greet one another without territorial conflicts. Outside these neutral areas, territory holders usually chase away stranger cats, at first by staring, hissing, and growling, and if that does not work, by short but noisy and violent attacks. Despite some cats cohabiting in colonies, they do not have a social survival strategy, or a pack mentality, and always hunt alone.[146]
Cat with an Alaskan Malamute dog However, some pet cats are poorly socialized. In particular, older cats may show aggressiveness towards newly arrived kittens, which may include biting and scratching; this type of behavior is known as feline asocial aggression.[147]
Though cats and dogs are often characterized as natural enemies, they can live together if correctly socialized.[148]
Life in proximity to humans and other domestic animals has led to a symbiotic social adaptation in cats, and cats may express great affection toward humans or other animals. Ethologically, the human keeper of a cat may function as a sort of surrogate for the cat's mother,[149] and adult housecats live their lives in a kind of extended kittenhood,[150] a form of behavioral neoteny. The high-pitched sounds housecats make to solicit food may mimic the cries of a hungry human infant, making them particularly hard for humans to ignore.[151]
Domestic cats' scent rubbing behavior towards humans or other cats is thought to be a feline means for social bonding.[152]
Communication Main article: Cat communication Domestic cats use many vocalizations for communication, including purring, trilling, hissing, growling/snarling, grunting, and several different forms of meowing.[7] (By contrast, feral cats are generally silent.)[153]:208 Their types of body language, including position of ears and tail, relaxation of the whole body, and kneading of the paws, are all indicators of mood. The tail and ears are particularly important social signal mechanisms in cats;[154][155] for example, a raised tail acts as a friendly greeting, and flattened ears indicates hostility. Tail-raising also indicates the cat's position in the group's social hierarchy, with dominant individuals raising their tails less often than subordinate animals.[155] Nose-to-nose touching is also a common greeting and may be followed by social grooming, which is solicited by one of the cats raising and tilting its head.[145]
Purring may have developed as an evolutionary advantage as a signalling mechanism of reassurance between mother cats and nursing kittens. Post-nursing cats often purr as a sign of contentment: when being petted, becoming relaxed,[156][157] or eating. The mechanism by which cats purr is elusive. The cat has no unique anatomical feature that is clearly responsible for the sound.[158] It was, until recent times, believed that only the cats of the Felis genus could purr. However, felids of the genus Panthera (tiger, lion, jaguar, and leopard) also produce non-continuous sounds, called chuffs, similar to purring, but only when exhaling.[159]
Grooming
The hooked papillae on a cat's tongue act like a hairbrush to help clean and detangle fur. File:Housecat Grooming Itself.webm A tabby housecat uses its brush-like tongue to groom itself, licking its fur to straighten it. Cats are known for spending considerable amounts of time licking their coat to keep it clean.[160] The cat's tongue has backwards-facing spines about 500 μm long, which are called papillae. These contain keratin which makes them rigid[161] so the papillae act like a hairbrush. Some cats, particularly longhaired cats, occasionally regurgitate hairballs of fur that have collected in their stomachs from grooming. These clumps of fur are usually sausage-shaped and about 2–3 cm (0.8–1.2 in) long. Hairballs can be prevented with remedies that ease elimination of the hair through the gut, as well as regular grooming of the coat with a comb or stiff brush.[160]
Fighting Among domestic cats, males are more likely to fight than females.[162] Among feral cats, the most common reason for cat fighting is competition between two males to mate with a female. In such cases, most fights are won by the heavier male.[163] Another common reason for fighting in domestic cats is the difficulty of establishing territories within a small home.[162] Female cats also fight over territory or to defend their kittens. Neutering will decrease or eliminate this behavior in many cases, suggesting that the behavior is linked to sex hormones.[164]
An arched back, raised fur and an open-mouthed hiss can all be signs of aggression in a domestic cat. When cats become aggressive, they try to make themselves appear larger and more threatening by raising their fur, arching their backs, turning sideways and hissing or spitting.[154] Often, the ears are pointed down and back to avoid damage to the inner ear and potentially listen for any changes behind them while focused forward. They may also vocalize loudly and bare their teeth in an effort to further intimidate their opponent. Fights usually consist of grappling and delivering powerful slaps to the face and body with the forepaws as well as bites. Cats also throw themselves to the ground in a defensive posture to rake their opponent's belly with their powerful hind legs.[165]
Serious damage is rare, as the fights are usually short in duration, with the loser running away with little more than a few scratches to the face and ears. However, fights for mating rights are typically more severe and injuries may include deep puncture wounds and lacerations. Normally, serious injuries from fighting are limited to infections of scratches and bites, though these can occasionally kill cats if untreated. In addition, bites are probably the main route of transmission of feline immunodeficiency virus.[166] Sexually active males are usually involved in many fights during their lives, and often have decidedly battered faces with obvious scars and cuts to their ears and nose.[167]
Hunting and feeding
A cat that is playing with a caught mouse. Cats play with their prey to weaken or exhaust them before making a kill.
A domestic cat with its prey Cats hunt small prey, primarily birds and rodents,[168] and are often used as a form of pest control.[169][170] Domestic cats are a major predator of wildlife in the United States, killing an estimated 1.4 to 3.7 billion birds and 6.9 to 20.7 billion mammals annually.[171][172] The bulk of predation in the United States is done by 80 million feral and stray cats. Effective measures to reduce this population are elusive, meeting opposition from cat enthusiasts.[171][172] In the case of free-ranging pets, equipping cats with bells and not letting them out at night will reduce wildlife predation.[168]
Free-fed feral cats and house cats tend to consume many small meals in a single day, although the frequency and size of meals varies between individuals.[146] Cats use two hunting strategies, either stalking prey actively, or waiting in ambush until an animal comes close enough to be captured.[173] Although it is not certain, the strategy used may depend on the prey species in the area, with cats waiting in ambush outside burrows, but tending to actively stalk birds.[174]:153
Perhaps the best known element of cats' hunting behavior, which is commonly misunderstood and often appalls cat owners because it looks like torture, is that cats often appear to "play" with prey by releasing it after capture. This behavior is due to an instinctive imperative to ensure that the prey is weak enough to be killed without endangering the cat.[175] This behavior is referred to in the idiom "cat-and-mouse game" or simply "cat and mouse".
Another poorly understood element of cat hunting behavior is the presentation of prey to human guardians. Ethologist Paul Leyhausen proposed that cats adopt humans into their social group and share excess kill with others in the group according to the dominance hierarchy, in which humans are reacted to as if they are at, or near, the top.[176] Anthropologist and zoologist Desmond Morris, in his 1986 book Catwatching, suggests, when cats bring home mice or birds, they are attempting to teach their human to hunt, or trying to help their human as if feeding "an elderly cat, or an inept kitten".[177][178] Morris's hypothesis is inconsistent with the fact that male cats also bring home prey, despite males having negligible involvement with raising kittens.[174]:153
Domestic cats select food based on its temperature, smell and texture; they dislike chilled foods and respond most strongly to moist foods rich in amino acids, which are similar to meat.[85][146] Cats may reject novel flavors (a response termed neophobia) and learn quickly to avoid foods that have tasted unpleasant in the past.[146] They may also avoid sugary foods and milk. Most adult cats are lactose intolerant; the sugars in milk are not easily digested and may cause soft stools or diarrhea.[146][179] They can also develop odd eating habits. Some cats like to eat or chew on other things, most commonly wool, but also plastic, cables, paper, string, aluminum foil, or even coal. This condition, pica, can threaten their health, depending on the amount and toxicity of the items eaten.[180][181]
Though cats usually prey on animals less than half their size, a feral cat in Australia has been photographed killing an adult pademelon of around the cat's weight at 4 kg (8.8 lb).[182]
Since cats lack sufficient lips to create suction,[183] they use a lapping method with the tongue to draw liquid upwards into their mouths. Lapping at a rate of four times a second, the cat touches the smooth tip of its tongue to the surface of the water, and quickly retracts it like a corkscrew, drawing water upwards.[184]
Running A veterinarian and columnist for Mercola Healthy Pets, Karen Shaw Becker, has compiled a list of the fastest and most athletic cat breeds. First is the Egyptian Mau, which can clock up to 30 miles per hour, faster than any other domestic cat breed in the world.[185][unreliable source] In descending order, Becker lists the other swift domestic cats: the Abyssinian cat, the Somali cat, the Bengal cat, the Savannah cat, the Manx cat ("He can jump and accelerate through the house like there's no tomorrow. Watch for his sharp turns and quick stops – you'll think he's a mini sports car in the shape of a cat."), the Siamese cat, the Ocicat, and the Oriental Shorthair.
The average house cat can outspeed the average house dog (excluding those born to run and race, such as the greyhound and the cheetah), but they excel at sprinting, not at long-distance running.
Play Main article: Cat play and toys File:Play fight between cats.webmhd.webm Play fight between kittens, age 14 weeks Domestic cats, especially young kittens, are known for their love of play. This behavior mimics hunting and is important in helping kittens learn to stalk, capture, and kill prey.[186] Cats also engage in play fighting, with each other and with humans. This behavior may be a way for cats to practice the skills needed for real combat, and might also reduce any fear they associate with launching attacks on other animals.[187]
Owing to the close similarity between play and hunting, cats prefer to play with objects that resemble prey, such as small furry toys that move rapidly, but rapidly lose interest (they become habituated) in a toy they have played with before.[188] Cats also tend to play with toys more when they are hungry.[189] String is often used as a toy, but if it is eaten, it can become caught at the base of the cat's tongue and then move into the intestines, a medical emergency which can cause serious illness, even death.[190] Owing to the risks posed by cats eating string, it is sometimes replaced with a laser pointer's dot, which cats may chase.[191]
Reproduction See also: Kitten
When cats mate, the tomcat (male) bites the scruff of the female's neck as she assumes a position conducive to mating known as lordosis behavior.
Radiography of a pregnant cat (about one month and a half) Female cats are seasonally polyestrous, which means they may have many periods of heat over the course of a year, the season beginning in spring and ending in late autumn. Heat periods occur about every two weeks and last about 4 to 7 days.[192] Multiple males will be attracted to a female in heat. The males will fight over her, and the victor wins the right to mate. At first, the female rejects the male, but eventually the female allows the male to mate. The female utters a loud yowl as the male pulls out of her because a male cat's penis has a band of about 120–150 backwards-pointing penile spines, which are about 1 mm long; upon withdrawal of the penis, the spines rake the walls of the female's vagina, which acts to induce ovulation. This act also occurs to clear the vagina of other sperm in the context of a second (or more) mating, thus giving the later males a larger chance of conception.[193]
After mating, the female washes her vulva thoroughly. If a male attempts to mate with her at this point, the female will attack him. After about 20 to 30 minutes, once the female is finished grooming, the cycle will repeat.[192]
Because ovulation is not always triggered by a single mating, females may not be impregnated by the first male with which they mate.[194] Furthermore, cats are superfecund; that is, a female may mate with more than one male when she is in heat, with the result that different kittens in a litter may have different fathers.[192]
A newborn kitten At 124 hours after conception, the morula forms. At 148 hours, early blastocysts form. At 10–12 days, implantation occurs.[195][196]
The gestation period for cats is between 64 and 67 days, with an average of 66 days.[197] The size of a litter usually is three to five kittens, with the first litter usually smaller than subsequent litters. Kittens are weaned between six and seven weeks old, and cats normally reach sexual maturity at 5–10 months (females) and to 5–7 months (males), although this can vary depending on breed.[192] Females can have two to three litters per year, so may produce up to 150 kittens in their breeding span of around ten years.[192]
Cats are ready to go to new homes at about 12 weeks of age,[198] when they are ready to leave their mother. They can be surgically sterilized (spayed or castrated) as early as 7 weeks to limit unwanted reproduction.[199] This surgery also prevents undesirable sex-related behavior, such as aggression, territory marking (spraying urine) in males and yowling (calling) in females. Traditionally, this surgery was performed at around six to nine months of age, but it is increasingly being performed before puberty, at about three to six months.[200] In the US, about 80% of household cats are neutered.[201]
Ecology Habitats
A cat in snowy weather Cats are a cosmopolitan species and are found across much of the world.[39] Geneticist Stephen James O'Brien, of the National Cancer Institute in Frederick, Maryland, remarked on how successful cats have been in evolutionary terms: "Cats are one of evolution's most charismatic creatures. They can live on the highest mountains and in the hottest deserts."[202] They are extremely adaptable and are now present on all continents except Antarctica, and on 118 of the 131 main groups of islands—even on isolated islands such as the Kerguelen Islands.[203][204]
Feral cats can live in forests, grasslands, tundra, coastal areas, agricultural land, scrublands, urban areas, and wetlands.[205] Their habitats even include small oceanic islands with no human inhabitants.[206] Further, the close relatives of domestic cats, the African wildcat (Felis silvestris lybica) and the Arabian sand cat (Felis margarita) both inhabit desert environments,[29] and domestic cats still show similar adaptations and behaviors.[32] The cat's ability to thrive in almost any terrestrial habitat has led to its designation as one of the world's worst invasive species.[207]
As domestic cats are little altered from wildcats, they can readily interbreed. This hybridization poses a danger to the genetic distinctiveness of some wildcat populations, particularly in Scotland and Hungary and possibly also the Iberian Peninsula.[42]
Feral cats Main article: Feral cat
Feral farm cat Feral cats are domestic cats that were born in or have reverted to a wild state. They are unfamiliar with and wary of humans and roam freely in urban and rural areas.[9] The numbers of feral cats is not known, but estimates of the US feral population range from 25 to 60 million.[9] Feral cats may live alone, but most are found in large colonies, which occupy a specific territory and are usually associated with a source of food.[208] Famous feral cat colonies are found in Rome around the Colosseum and Forum Romanum, with cats at some of these sites being fed and given medical attention by volunteers.[209]
Public attitudes towards feral cats vary widely, ranging from seeing them as free-ranging pets, to regarding them as vermin.[210] One common approach to reducing the feral cat population is termed 'trap-neuter-return', where the cats are trapped, neutered, immunized against diseases such as rabies and the feline Panleukopenia and Leukemia viruses, and then released.[211] Before releasing them back into their feral colonies, the attending veterinarian often nips the tip off one ear to mark it as neutered and inoculated, since these cats may be trapped again. Volunteers continue to feed and give care to these cats throughout their lives. Given this support, their lifespans are increased, and behavior and nuisance problems caused by competition for food are reduced.[208]
Impact on prey species
Carrying half of a rabbit To date, little scientific data is available to assess the impact of cat predation on prey populations outside of agricultural situations. Even well-fed domestic cats may hunt and kill, mainly catching small mammals, but also birds, amphibians, reptiles, fish, and invertebrates.[168][212] Hunting by domestic cats may be contributing to the decline in the numbers of birds in urban areas, although the importance of this effect remains controversial.[213] In the wild, the introduction of feral cats during human settlement can threaten native species with extinction.[206] In many cases, controlling or eliminating the populations of non-native cats can produce a rapid recovery in native animals.[214] However, the ecological role of introduced cats can be more complicated. For example, cats can control the numbers of rats, which also prey on birds' eggs and young, so a cat population can protect an endangered bird species by suppressing mesopredators.[215]
In isolated landmasses, such as Australasia, there are often no other native, medium-sized quadrupedal predators (including other feline species); this tends to exacerbate the impact of feral cats on small native animals.[216] Native species such as the New Zealand kakapo and the Australian bettong, for example, tend to be more ecologically vulnerable and behaviorally "naive", when faced with predation by cats.[217] Feral cats have had a major impact on these native species and have played a leading role in the endangerment and extinction of many animals.[218]
Even in places with ancient and numerous cat populations, such as Western Europe, cats appear to be growing in number and independently of their environments' carrying capacity (such as the numbers of prey available).[219][220] This may be explained, at least in part, by an abundance of food, from sources including feeding by pet owners and scavenging. For instance, research in Britain suggests that a high proportion of cats hunt only "recreationally"[220], and in South Sweden, where research in 1982 found that the population density of cats was as high as 2,000 per square kilometre (5,200/sq mi).[219]
In agricultural settings, cats can be effective at keeping mouse and rat populations low, but only if rodent harborage locations are kept under control.[221][222] While cats are effective at preventing rodent population explosions, they are not effective for eliminating pre-existing severe infestations.[223]
Impact on birds
A black cat eating a house sparrow The domestic cat is a significant predator of birds. UK assessments indicate they may be accountable for an estimated 64.8 million bird deaths each year.[168] A 2012 study suggests feral cats may kill several billion birds each year in the United States.[224] Certain species appear more susceptible than others; for example, 30% of house sparrow mortality is linked to the domestic cat.[225] In the recovery of ringed robins (Erithacus rubecula) and dunnocks (Prunella modularis), 31% of deaths were a result of cat predation.[226] In parts of North America, the presence of larger carnivores such as coyotes which prey on cats and other small predators reduces the effect of predation by cats and other small predators such as opossums and raccoons on bird numbers and variety.[227] The proposal that cat populations will increase when the numbers of these top predators decline is called the mesopredator release hypothesis.
On islands, birds can contribute as much as 60% of a cat's diet.[228] In nearly all cases, however, the cat cannot be identified as the sole cause for reducing the numbers of island birds, and in some instances, eradication of cats has caused a 'mesopredator release' effect;[229] where the suppression of top carnivores creates an abundance of smaller predators that cause a severe decline in their shared prey. Domestic cats are, however, known to be a contributing factor to the decline of many species, a factor that has ultimately led, in some cases, to extinction. The South Island piopio, Chatham rail,[226] the New Zealand merganser,[230] and the common diving petrel[231] are a few from a long list, with the most extreme case being the flightless Lyall's wren, which was driven to extinction only a few years after its discovery.[232][233]
Some of the same factors that have promoted adaptive radiation of island avifauna over evolutionary time appear to promote vulnerability to non-native species in modern time. The susceptibility of many island birds is undoubtedly due to evolution in the absence of mainland predators, competitors, diseases, and parasites, in addition to lower reproductive rates and extended incubation periods.[234] The loss of flight, or reduced flying ability is also characteristic of many island endemics.[235] These biological aspects have increased vulnerability to extinction in the presence of introduced species, such as the domestic cat.[236] Equally, behavioral traits exhibited by island species, such as "predatory naivety"[237] and ground-nesting,[234] have also contributed to their susceptibility.
Interaction with humans Main article: Human interaction with cats
Cats and people Cats are common pets throughout the world, and their worldwide population exceeds 500 million.[13] Although cat guardianship has commonly been associated with women,[238] a 2007 Gallup poll reported that men and women in the United States of America were equally likely to own a cat.[239]
As well as being kept as pets, cats are also used in the international fur[240] and leather industries for making coats, hats, blankets, and stuffed toys;[241] and shoes, gloves, and musical instruments respectively[242] (about 24 cats are needed to make a cat-fur coat).[243] This use has been outlawed in the United States, Australia, and the European Union.[244] Cat pelts have been used for superstitious purposes as part of the practise of witchcraft,[245] and are still made into blankets in Switzerland as folk remedies believed to help rheumatism.[246] In the Western intellectual tradition, the idea of cats as everyday objects have served to illustrate problems of quantum mechanics in the Schrödinger's cat thought experiment.
A few attempts to build a cat census have been made over the years, both through associations or national and international organizations (such as the Canadian Federation of Humane Societies's one[247]) and over the Internet,[248][249] but such a task does not seem simple to achieve. General estimates for the global population of domestic cats range widely from anywhere between 200 million to 600 million.[250][251][252][253][254][255]
Cat show Main article: Cat show A cat show is a judged event where the owners of cats compete to win titles in various cat registering organizations by entering their cats to be judged after a breed standard.[256][257] Both pedigreed and companion (or moggy) cats are admissible, although the rules differ from organization to organization. Cats are compared to a breed standard,[258] and the owners of those judged to be closest to it are awarded a prize. Moggies are judged based on their temperament. Often, at the end of the year, all of the points accrued at various shows are added up and more national and regional titles are awarded.
Cat café Main article: Cat café A cat café is a theme café whose attraction is cats that can be watched and played with.[259] Patrons pay a cover fee, generally hourly and thus cat cafés can be seen as a form of supervised indoor pet rental.
Ailurophobia Main article: Ailurophobia Ailurophobia is a human phobia of cats; however, the term is often associated with humans that have a hatred of cats.[260]
Cat bites Main article: Cat bite Cats may bite humans when provoked, during play or when aggressive. Complications from cat bites can develop.[261] A cat bite differs from the bites of other pets. This is because the teeth of a cat are sharp and pointed causing deep punctures. Skin usually closes rapidly over the bite and traps microorganisms that cause infection.[262][261]
Infections transmitted from cats to humans Main article: Feline zoonosis Cats can be infected or infested with viruses, bacteria, fungus, protozoans, arthropods or worms that can transmit diseases to humans.[263] In some cases, the cat exhibits no symptoms of the disease,[264] However, the same disease can then become evident in a human. The likelihood that a person will become diseased depends on the age and immune status of the person. Humans who have cats living in their home or in close association are more likely to become infected, however, those who do not keep cats as pets might also acquire infections from cat feces and parasites exiting the cat's body.[263][265] Some of the infections of most concern include salmonella, cat scratch disease and toxoplasmosis.[264]
History and mythology Main articles: Cultural depictions of cats and Cats in ancient Egypt
The ancient Egyptians mummified dead cats out of respect in the same way that they mummified people.[266]
Ancient Roman mosaic of a cat killing a partridge from the House of the Faun in Pompeii
A 19th-century drawing of a tabby cat Traditionally, historians tended to think ancient Egypt was the site of cat domestication, owing to the clear depictions of house cats in Egyptian paintings about 3,600 years old.[29] However, in 2004, a Neolithic grave excavated in Shillourokambos, Cyprus, contained the skeletons, laid close to one another, of both a human and a cat. The grave is estimated to be 9,500 years old, pushing back the earliest known feline–human association significantly.[16][267][268] The cat specimen is large and closely resembles the African wildcat, rather than present-day domestic cats. This discovery, combined with genetic studies, suggests cats were probably domesticated in the Middle East, in the Fertile Crescent around the time of the development of agriculture, and then were brought to Cyprus and Egypt.[15][20] Direct evidence for the domestication of cats 5,300 years ago in Quanhucun, China has been published by archaeologists and paleontologists from the University of Washington and Chinese Academy of Sciences. The cats are believed to have been attracted to the village by rodents, which in turn were attracted by grain cultivated and stored by humans.[269]
In ancient Egypt, cats were sacred animals, with the goddess Bastet often depicted in cat form, sometimes taking on the war-like aspect of a lioness.[270]:220 Killing a cat was absolutely forbidden[266] and the Greek historian Herodotus reports that, whenever a household cat died, the entire family would mourn and shave their eyebrows.[266] Families took their dead cats to the sacred city of Bubastis,[266] where they were embalmed and buried in sacred repositories.[266] Domestic cats were probably first introduced to Greece and southern Italy in the fifth century BC by the Phoenicians.[271] The earliest unmistakable evidence of the Greeks having domestic cats comes from two coins from Magna Graecia dating to the mid-fifth century BC showing Iokastos and Phalanthos, the legendary founders of Rhegion and Taras respectively, playing with their pet cats.[272]:57–58[273]
Housecats seem to have been extremely rare among the ancient Greeks and Romans;[273] Herodotus expressed astonishment at the domestic cats in Egypt, because he had only ever seen wildcats.[273] Even during later times, weasels were far more commonly kept as pets[273] and weasels, not cats, were seen as the ideal rodent-killers.[273] The usual ancient Greek word for "cat" was ailouros, meaning "thing with the waving tail",[272]:57[273] but this word could also be applied to any of the "various long-tailed carnivores kept for catching mice".[273] Cats are rarely mentioned in ancient Greek literature,[273] but Aristotle does remark in his History of Animals that "female cats are naturally lecherous."[272]:74[273] The Greeks later syncretized their own goddess Artemis with the Egyptian goddess Bastet, adopting Bastet's associations with cats and ascribing them to Artemis.[272]:77–79 In Ovid's Metamorphoses, when the gods flee to Egypt and take animal forms, the goddess Diana (the Roman equivalent of Artemis) turns into a cat.[272]:79 Cats eventually displaced ferrets as the pest control of choice because they were more pleasant to have around the house and were more enthusiastic hunters of mice.[274] During the Middle Ages, many of Artemis's associations with cats were grafted onto the Virgin Mary.[274] Cats are often shown in icons of Annunciation and of the Holy Family[274] and, according to Italian folklore, on the same night that Mary gave birth to Jesus, a virgin cat in Bethlehem gave birth to a kitten.[274] Domestic cats were spread throughout much of the rest of the world during the Age of Discovery, as ships' cats were carried on sailing ships to control shipboard rodents and as good-luck charms.[270]:223
Several ancient religions believed cats are exalted souls, companions or guides for humans, that are all-knowing but mute so they cannot influence decisions made by humans. In Japan, the maneki neko cat is a symbol of good fortune.[275] In Norse mythology, Freyja, the goddess of love, beauty, and fertility, is depicted as riding a chariot drawn by cats.[276] In Jewish legend, the first cat was living in the house of the first man Adam as a pet that got rid of mice.[277] The cat was once partnering with the first dog before the latter broke an oath they had made which resulted in enmity between the descendants of these two animals.[277] It is also written that neither cats nor foxes are represented in the water, while every other animal has an incarnation species in the water.[277] Although no species are sacred in Islam, cats are revered by Muslims. Some Western writers have stated Muhammad had a favorite cat, Muezza.[278] He is reported to have loved cats so much, "he would do without his cloak rather than disturb one that was sleeping on it".[279] The story has no origin in early Muslim writers, and seems to confuse a story of a later Sufi saint, Ahmed ar-Rifa'i, centuries after Muhammad.[280] One of the companions of Muhammad was known as "Abu Hurayrah" (Father of the Kitten), in reference to his documented affection to cats.[281]
Superstitions and cat burning
Some cultures are superstitious about black cats, ascribing either good or bad luck to them. Many cultures have negative superstitions about cats. An example would be the belief that a black cat "crossing one's path" leads to bad luck, or that cats are witches' familiars used to augment a witch's powers and skills. The killing of cats in Medieval Ypres, Belgium, is commemorated in the innocuous present-day Kattenstoet (cat parade).[282] In medieval France, cats would be burnt alive as a form of entertainment. According to Norman Davies, the assembled people "shrieked with laughter as the animals, howling with pain, were singed, roasted, and finally carbonized".[283]
"It was the custom to burn a basket, barrel, or sack full of live cats, which was hung from a tall mast in the midst of the bonfire; sometimes a fox was burned. The people collected the embers and ashes of the fire and took them home, believing that they brought good luck. The French kings often witnessed these spectacles and even lit the bonfire with their own hands. In 1648 Louis XIV, crowned with a wreath of roses and carrying a bunch of roses in his hand, kindled the fire, danced at it and partook of the banquet afterwards in the town hall. But this was the last occasion when a monarch presided at the midsummer bonfire in Paris. At Metz midsummer fires were lighted with great pomp on the esplanade, and a dozen cats, enclosed in wicker cages, were burned alive in them, to the amusement of the people. Similarly at Gap, in the department of the Hautes-Alpes, cats used to be roasted over the midsummer bonfire."[284]
According to a myth in many cultures, cats have multiple lives. In many countries, they are believed to have nine lives, but in Italy, Germany, Greece, Brazil and some Spanish-speaking regions, they are said to have seven lives,[285][286] while in Turkish and Arabic traditions, the number of lives is six.[287] The myth is attributed to the natural suppleness and swiftness cats exhibit to escape life-threatening situations. Also lending credence to this myth is the fact that falling cats often land on their feet, using an instinctive righting reflex to twist their bodies around. Nonetheless, cats can still be injured or killed by a high fall.[288]
See also
Book: Cat icon Cats portal icon Mammals portal Aging in cats Animal testing on cats Animal track Cancer in cats Cat and mouse (cat-and-mouse game) Cat burning Cat intelligence Cat lady Cats and the Internet Dog–cat relationship Dried cat List of cat breeds List of cat documentaries List of cats List of fictional cats and felines Pet door including cat flap Pet first aid Popular cat names Trap-neuter-return Cats by location Cats in ancient Egypt Cats in Australia Cats in New Zealand Cats in the United States Notes Taurine is sometimes called an amino acid, and indeed is an acid containing an amino group, it is not an amino acid in the usual biochemical meaning of the term, which refers to compounds containing both an amino and a carboxyl group.[90] References Wozencraft, W.C. (2005). "Species Felis catus". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 534–535. ISBN 978-0-8018-8221-0. 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A journey through the circulatory system.
Another adventure with Richard Harrison… A journey through the circulatory system.
Richard Harrison, inventor of the one and only shrinkinator, has long since upgraded the shrinkinator’s shrinking effects. Lasting up to 48 hours and can shrink down to the size of a singleerythrocyte.(Red blood cell) And not only that, there is a regrowth delay, that lasts about 2 hours in case of any erhm, certain emergencies. So no more RIP test subjects. Speaking of which, Richard Harrison’s grandson, a 65 year old diabetic with a severely high risk of cardiac failure, is in desperate need of medical attention. So Rick’s plan for today, is to swim through the bloodstream of this unhealthy sack of plaque, and clean out the unnecessary blockage within the chambers of the heart.
Rick sets off for his adventure, and packs his lunch for the day, he is ready for take off. He stand in front of the shrinkinator’s ray, hops in his hovercraft-type-thing and poof. Richard Harrison is nowhere to be seen. He flies with the air currents and flies through his grandsons nostril as he breathes in… a perfect entrance to the lungs, so that he can absorb into the bloodstream.
After about 3 minutes of swimming through gross mucous, richard finally gets to the throat, there are 2 ways to go, the esophagus, or the trachea. Unfortunately, Richard has absolutely zero clue which is which… the lifesize eye view is a lot more difficult to see than a nicely written diagram. Oh wait, never mind, the epiglottis is moving back and forth. Opening and closing, weird, gross. As it opens a slight breeze of air goes in with it, Rick takes his chances now and zooms within, he makes it.
Now traveling down the trachea, Rick’s vehicle thing he’s driving is being beaten lifeless by a shitton of hair-like figures trying to prevent his entrance, the cilia. There’s a long row of them side by side, going up along the walls, they’re not the strongest, mainly just stirring up air currents. No match for Ricks hovercraft thing. He flies down through the long tube of hairs, and finds his way into the entrance of the lungs, he flies down, and takes a left turn. He enters his way through thebronchial tubes and finds a bunch of little gross clumps of sponge-like tissue, there’s hundreds of millions of them, all side by side, these must be entrances to the capillaries, this is where the gas exchange happens, this is how Richard is going to find his way to the heart and finally clean out the gunk.
Oh crap there’s a problem. There is a very thick layer of black sticky mess coating them, this layer keeps growing and growing as he gets closer towards them. They are like a blockage, there’s no way in hell Rick is ever going to get through this mess of tar. This unhealthy lifestyle is filled with smoking, and it’s clearly affecting the lungs. Luckily, Rick has a plan, his hovercraft has a hefty little laser attachment to it. He releases the chamber, and the big pointed sci-fi style canon turns toward the the black sticky mess, and drills a hole straight through it. poof He disengages the laser, and proceeds to diffuse through the little tentacle thing and enters the capillary!
This part is very quick, as he flows through the heart within 2 beets, he barely saw anything. Holy Jeez. Does the heart ever have some pressure in it. It was like flying through one of those futuristic tubes. In-floop-Out. So here’s the attempted slow motion description.
Okay. So basically…
Richard Harrison, is now flowing through the blood. It’s, strange. He’s approximately the exact same size as the other RBC’s(Red blood cells) and he is flowing past them, as he transfers from the capillaries to the venules, he can see the strange figure of them, they’re like little donuts, but pressed in the middle rather than a hole, and oval like in shape. Also, while going through, he could literally, see the gas exchange happen. It was like, watching a bunch of balls go through a tube, into larger balls, yet simultaneously other balls were coming back out of the giant balls through the tube and flowing back into yet another tube going the opposite direction. Very, very confusing. Also, the fact that blood is purple when there’s no oxygen, nope. Just a very, very dark shade of red. Almost blueish shade, but still red. ‘Twas strange, you could almost see the color change, like a red light bulb turning on and off. Off and dark with no oxygen(aka power) And on and glowing brightly when there is oxygen. Quite interesting.
Anywho, going from the arterioles, a very short route, Rick enters one of the legendary Pulmonary Veins, the only veins that actually carry oxygen rich blood, and now Richard rich blood! pun city
This is where it gets confusing, Rick understood lots about biology and is about as educated as a 205 year old man can be, but this is one thing that he can never understand. The complexity of the human heart. After first entering the veins, he reengages his laser and prepares for a heavy duty cleaning… Rick never ended up getting the chance to. After leaving these veins, and entering the Left Ventricle of the heart, he instantly gets a forced push with tremendous speed straight towards an opening, the opening of the Left Atrioventricular Valve, it’s almost as if the top left side of the hard completely squeezed all the blood through the valve. After flying through this tunnel, there is a sudden stop. This looks clean, no need for laser cleaning here it seams. The amount of pressure on the left side of the heart pretty much cleans itself out it seams. The Left Ventricle doesn’t need any cleaning today. So just as soon as Rick disengages his laser, BUMP another beat. He flies straight through the Semilunar Valve and enters through the Aorta, and flies down through the aortic arch and leaves the heart through theDescending Aorta. Goodbye heart, for now.
Now, with each thrust of his grandsons unhealthy, annoyingly fast pulse. Rick flies through the arteries, in which Rick believes to be currently running through the Common Iliac Artery, which runs through the left & right abdomin area. He sees something, it’s like a little change of rout, kind of like one of those train track movers, except stationary and the RBC’s either pass it, or take it. Rick’s main goal is to get back to the heart and clean the right side, so he takes the turn. He enters an Arteriole, the gateway to the capillary beds, so that he can proceed back! Unfortunately however, Rick seams to face one small problem. There is a very, thick, blockage. It’s a crusty yellow thick layer, the tubes are so thin, the blood is barely going through. No wonder this guy's blood pressure is so high, the blood can’t go through. No biggie, this is the reason Rick brought a laser!
He engages it once again, and starts to fire away at the layers of Plaque build up along the walls. Disgusting. After about what seems like an hour of removing heart attack fluid, the blood flow is relatively back to normal. Rick flows along!
He reaches the Capillary Beds, a huge bundle of what seems like billions of tiny fibres, this is where the real cell/cell gas exchange happens. Rick, as he did last time, diffused himself through the walls of the capillaries, and rushed through the thin tube until he found himself in yet another Venule. Holly greasy matters of shit. This is clogged up. It’s even worse than the lungs were of tar. The amount of plaque on the walls of the venules is so tragically thick, Ricks laser couldn’t even penetrate it fully. Jeezas, this is thick. Rick tries his best to rid of as much plaque as scientifically possible. He did get most of it, but there’s still some there. He then transfers through to the Veins, a one way ticket back to the heart!
Unfortunately, yet another problem has been revealed. The thin walls of the veins, aren’t enough to withstand the pressure of the heart, so they require valves to ensure a one way route. However, due to Rick’s grandson’s lack of healthy lifestyle choices... every, single, valve, is just coated in a dreadfully thick layer of plaque. Rick is absolutely mortified. He’s never been in so much disgust in his life. Luckily, the old man has a heartpun city, and decided to spend 6 hours, doing absolutely nothing but cleaning. Just scrubbing every last bit of plaque of each and every single valve he sees, the lines are almost endless. But he finally succeeds. So far within Rick’s journey, he is about 23 hours. 8 minutes and 47 seconds in. Thank lord almighty rick updated his shrinkinator. However, after all the cleaning he’s done so far, he doesn’t even want to witness the horrors that lurk within… the right side of the heart.
Richard Harrison, finally, finds his way to the rout, of the body's largest vein. The Vena Cava. In this case, he flows up, towards the Inferior Vena Cava. Luckily, for Rick, there seems to be minimal plaque within this, but he still awaits with his laser cleaning cannon ready fire. Within a heartbeat,pun city Rick is pushed through into the Right Atrium, however, to Rick’s surprise, there is yet, no plaque, this is strange, why is there plaque in every other part of the circulatory system, except for the heart? This makes Rick very skeptical. He makes his way through anotherAtrioventricular Valve into the Right Ventricle… still no plaque. And with yet another pulse and squeezing motion, he is swirled out through theSemilunar Valve and sent directly through thePulmonary Arteries. He goes through the right one this time, into the right lung. He escapes from the gas exchange and proceeds his way out the bronchiole tubes. Rick decides he’s going to clean his grandsons lungs! Just being generous.
After a long ass time of polishing, the lungs seem to be functioning at full capacity again! However, Rick’s skepticism continues to grow as to why the heart seems to have no noticeable plaque build up at all.
But then, all of a sudden, it all comes to him at once. Last week, he recently did a heart transplant surgery on a Llama. He remembered one vague detail about it. The amount of fat buildup coating the outside lining of the heart. This must be where all the plaque goes? Maybe. So Rick turns around and makes his journey again! There’s still 16 hours left before regrowth, so he has plenty of time to clean!
(Basically this story is long enough as it is, I’m just going to skip to the part where he get’s back into the pulmonary veins)
Rick makes a very small microscopic puncture through the walls of the pulmonary veins, and enters the empty space of the chest cavity, Rick can see the plasma reacting with the puncture hole, instantly covering it, interesting, as if thefibrinogen in the plasma were creating little line segments covering over the puncture wound and the thrombocytes(platelets) react with it and cause little bits of clumped blood to cover it. Anywho, back to cleaning the heart.
Rick flies up, he can see the heart wide and clear. Holy sweet mother mackerel salmon fillets. It’s… disgusting. Rick has seen a lot in his days, but never anything this disgusting. However, out of true love for his grandsons unhealthy life. He starts cleaning right away!
It’s been about 9 hours. Of doing absolutely nothing but shooting a goddamned laser at crusty yellow lining. The heart, is now officially back to a healthy state! YES! Rick’s mission is complete, and with only 7 hours to spare! Phew. Rick punctures back into the heart, and flies through the 2 left chambers and goes up this time through one of the arteries within the Aorta. This however, is not good news for rick…
After flowing through, Rick finds his way into one of the many veins within the brain. This is very fascinating! He travels through, cleaning bits and scrummies of plaque throughout, however. Rick finds himself in a very awkward position. He seemed to have drifted off into a brain receptor. Specifically a 5ht2 receptor. Now, if Rick were the exact same shape and size as a serotonin neuron, he’d happily flow through the neurotransmitter with ease. Unfortunately however, Rick isn’t a neuron. He’s a foreign invader.(technically) This, sets off a brain signal, stating that there is a problem… awe sheit.
Rick, is then immediately flown away, through another vein, and then makes a sudden stop, he is now officially being engulfed by a leukocyte.(White Blood Cell) This specific type of WBC(White blood cell) is called a Macrophage, it quite literally, engulfed ricks hovercraft. Luckily for rick, his hovercraft is quite sturdy, and can easily escape, however out of sheer curiosity on how this immune response is about to work, he decides to go with the flow and watch what happens, after all he still has 6 and a half hours.
Something funny happens, most bacteria have specific antigens on them, Rick’s hovercraft however, does not. What is this macrophage going to do to show the identity? Lol, it creates an exact replica of Rick’s laser, and grows multiple copies of it along the outside cell membrane. Interesting. It seems that Rick’s laser is also in fact, his antigen. Now more interesting things happen!
There are now several other spheres surrounding this macrophage, and they are making moulds of the laser within the cell membrane, and others just sitting around. These must be the Helper T &B cells. After this, most of these spheres deplenish, however very shortly afterwards, what seems like hundreds of little dots, start to come toward. The macrophage in an instant, disappeared, as if it just like teleported to another dimension. Strange.
These dots, are firing, little rods, hundreds even thousands at a time directly towards Rick’s hovercraft, directly aimed at the laser cannon. Looks like the globulins in the plasma are producing antibodies at an exponential rate, dumb cells, they think he’s a pathogen. Little do they know, his laser is a… what the f. The antibodies actually managed to disable the laser. This isn’t good. Rick panics for a second, but remembers his hovercraft can’t be destroyed by a human body. So he relaxes for a minute, and decides to wait it out and see how this finishes...
It doesn’t. Rick is now basically floating around the circulatory system, his hovercraft now 100% disabled. He can’t do anything. Time is running out. He’s been floating around helplessly around the whole circulatory system for a good 4 hours now. He only has an hour and a half left before resize, if he doesn’t find a way out of his grandsons body soon, all his hard work and attempt to save him from unhealthy lifestyle will be pointless. But what can he do, these antibodies somehow managed to disable all functions of his hovercraft. There’s absolutely nothing. He is rendered useless. Rick is going to kill his grandson.
But wait, all of a sudden, yet another macrophage comes along, and engulfs him yet again. However, this macrophage is going somewhere. Rick gains hope. The macrophage travels through the bloodstream, he is now entering the heart, again, and being pumped down through the descending aorta, travels through more arterioles, and another branch of capillaries. But this time, there’s hope. The macrophage couldn’t digest the thick metal used in the outer coating of the hovercraft, so it sent him straight to the liver, so that he can be sent through the waste tube.
Rick is now anxious, anxious to get out, but he is still disabled, there is absolutely nothing he can do. Except for wait it out. Only one problem, there is only 25 minutes left before resize… how is he ever going to make it out in time? Rick accepts his grandsons fate right then, right there, starts to tear up a little. There is no way in hell, that he is ever going to make it out in time. Rick finds himself in total defeat. He should’ve just left when he was done, rather than watch the stupid immune response caused by him.
After weeping, dwelling and feelings of regret, there is approximately 5 minutes before resize. It’s final, Rick killed the one man he tried to save…
But then, suddenly, all at once, the liver dumped all of its waste(Bile), through a tube of tissue, into theGall Bladder. Usually, the bile would sit there, however, thanks to the unhealthy lifestyle of his grandson, the undercooked double quarter pounder with cheese finally pulled through!DIARRHEA! The bile instantly flowed through to the small intestines rushing fast, minimal nutrients being absorbed by the villi of the intestinal lining, the liquid solution dumps through a sphincter into the large intestine. Good lord. Rick, as happy as he is right now. Has never, in his life, experienced such mortifying stench in his life. It’s as if all the outhouses in the world were dumped, into one tube. It smelled as if, a whole concentration camp worth of dead bodies were stuffed in a pile and left to rot. The stench was so horrid, that even people without scent glands started to cry. One can not simply, describe, the pure horror of how bad this stank really is. All Rick wanted was to get the hell out of there.
The pile of waste, is now moving at a less speedy, pace, peristalsis keeping everything in place running semi-smoothly. There is another opening, it goes straight downwards. This must be therectum. Almost there, almost there… there’s 22 seconds left before resize. Rick prays to his scientific god Kim Il Song, “Please, please get to the washroom pl…”
fart
The pile of what is now liquid feces, is instantaneously shot out of the anal sphincter at tremendous speed directly into the toilet of a McDonalds restroom. Steve(Rick’s grandson’s name, should’ve mentioned that earlier) gets up off of the toilet, and proceeds to wipe his bum and…
poof
Rick barely made it, but he did make it for sure. The whole stall now completely destroyed. The first thing Rick does, is immediately jumps out of his hovercraft, and power pukes, hard. Straight down.
After a good 3 minutes of puking, the McDonalds manager walks in to see what all the ruckus was, with complete and utter shock, she slowly backs away and proceeds to call 911.
Rick looks up. Something is weird. Where’s Steve? He just took a #2, where could he have gone?
Rick looks down. There he is. In a puddle of his grandfather's puke. Steve died instantly of cardiac arrest after being scared shitlesspun city by Ricks sudden surprise visit.
Th3 3nd.
~anonymous

This is going to be insanely long and borderline incoherent, but what the hell. Time to break out the old dwarven theories and take bets on which ones will go down in flames tomorrow! ヾ(@w@)ｼ Hurray!
 
Theory #1: Sandal is the modern-day reincarnation of June, aka Andoral.
 
We’re not likely to get much on this one even if Sandal does appear in Descent. Still, what little we have seems to support the possibility, as it would help explain both his solitary survival in the Deep Roads and his untaught, savant-level skill working with lyrium- much like Sera/Andruil and her preternatural gift for marksmanship.
 
Theory #2: June was the progenitor of the Dwarven race, responsible for crafting the Pantheon’s idols, avatars, and weapons of war.
 
Solid lore on June is bizarrely hard to come by, but this one is largely accepted as “common sense”. Again, the few threads we have seem to point to the same conclusion: the dwarves’ underground domain fits well with June’s primary Greco-Roman reflection in the Pantheon (Hephaestus/Vulcan) and his mosaic in the Temple of Mythal seems to drop additional hints about his identity and purpose within the Pantheon.
 
Mosaic
 
1) June is depicted with a distinctive and (almost) unique spiraling pattern of tiles on his forehead- a distinction that may well be an early version of a tranquility brand. Severance from the fade would be expected in the progenitor of the dwarven race, and may have been self-inflicted, given that June is described as having “created himself”. The only other member of the Pantheon that shares this tile pattern is Andruil- and as discussed elsewhere, its interpretation as a tranquility brand seems to fit in both cases, though it’s likely the purpose of hers was punishment, not protection.
 
2) Of all the Pantheon members, only June’s face is covered in silver tiles, possibly intended to represent a beard. (Mythal’s children are silver-faced as well, but that's more likely a representation of vallaslin.)
 
3) The item on the anvil appears to have vaguely deer-like features, possibly suggesting “OGS vessel” collaboration with Ghilan’nain. Alternatively, this could imply the creation of totemic statuary designed to be animated by the OGS of Pantheon members, who would have preferred increasingly indirect interaction with subordinates and followers as civil governance evolved into religious worship.
 
4) Finally, the round shape at the bottom left brings to mind Solas’ orb, as well as the sphere that hovers over Fen’Harel’s head in his mosaic. As craftsman of the Pantheon, it seems to naturally follow that June would have been responsible for crafting the Pantheon’s respective idols. Other artifacts of great power, including Andruil’s weapons and armor of the Void, may also have been his work.
 
Which brings up another item…
 
Theory #3: June crafted the red lyrium idol, and Kal-Sharok dwarves shattered it.
 
The Red Lyrium idol - theorized to have been Elgar’nan’s- shows obvious signs of fracture at its base. At some point between the fall of Arlathan and its rediscovery, it seems clear that some faction (most likely dwarves, given where the shattered idol was recovered) attempted to destroy it. The answer to the question “why?” could be as simple as mistrust of red lyrium’s effects, or it may be more.
 
One theory holds that the high priests of Elgar’nan managed to flee the fall of Arlathan, bringing his idol with them for safekeeping as they took refuge with the dwarves of Cad’halash. We know Cad’halash was subsequently destroyed by Kal Sharok for harboring those refugees, but their reasons may have had very little to do with Tevinter. Tellingly, we find post-fall elvhen art in the cells of the “Grey Warden” prison where Hawke encounters Corypheus- a prison obviously built, used, and abandoned by dwarves long before the Wardens repurposed it. We also find a potential additional reason for the attempted destruction of the idol in the The Hunt of the Fell Wolf codex, which suggests powerful spirits might only be truly defeated when two conditions are met: its physical body slain and associated “demon-stone” shattered.
 
The destruction of the red lyrium idol may have had unintended consequences, exposing the dwarves present to the maddening effects of red lyrium. Potential spread may have been the factor that prompted the sealing of the Primeval Thaig, trapping all those within, infected or not. This, then, may be the source of the Profane. Cut off from external sustenance, these dwarves would have had only one option for survival: to “feast upon the Gods”. In consuming red lyrium (the blighted Blood of the Sun) they might have connected themselves to the dark fade- a mirror of Cole’s sustaining connection to the normal fade we know, the Fade of the Earth.
 
Theory #4: The Titans were June-crafted war golems dating from Falon’Din’s failed rebellion, powered by the souls of dwarves.
 
Written up here.
 
Theory #5: Titans were repurposed after the fall of Arlathan, used by a corrupt faction of dwarves to enslave humans.
 
This one is… odd. If we start with the assumption that June-crafted Titans are the inspiration for the double-sided Tevinter statues we find around Thedas, the statuary we find in Kirkwall is pretty explicit: they’re prominently displayed in the Gallows, watching over slaves with distinctly human ears. Though appropriated and built upon by Tevinter and later human populations, the dwarvishness of the underlying construction in Kirkwall is in no way limited to the modern Dwarven quarter.
 
Corypheus’ early confusion also seems to corroborate the idea. After noting that party members are human, he can only imagine two possibilities: "citizens of the [Tevinter] Empire?" or “Slaves, then, to the dwarves?”
 
Still, this theory leaves a lot of loose threads. If human slavery under the dwarves was widespread practice during Corypheus’ time, how was it so completely erased from historic record in the ages since? What happened to this dwarvish faction? Could they have moved west, their descendants forming the Voshai? If so, what forced them to abandon Kirkwall?
 
Theory #6: Dwarves are the immune system of the Stone, which is the unborn child of the primordial being Earth.
 
Soooo... (; =w=) This is a big one, and requires a good chunk of background theory to be comprehensible. I'll try to condense the main points:
 
This theory holds that the Sun and Earth referenced in the earliest Dalish myths are literal beings: enormous, powerful, and draconic. The Earth was mortally wounded in a primordial battle between Elgar’nan and the Sun – the first of Mythal’s many triad-deaths, as she (a fragment of the Earth’s soul) emerged from the Fade “ocean” (the Earth’s spirit) after the death of her physical form. The Earth’s body, source of lyrium, underlies the continent of Thedas, and may form the bulk of the planet itself. The Stone, her unborn child, may currently be carrying the Sun’s OGS in what would have been the first, primordial instance of the Dark Ritual. Consequently, one interpretation of the coming “dawn” in Andrastean religion may be the Sun’s rebirth via the Stone. Worryingly, just as valid would be the release of the False Sun, Elgar’nan, from the Dark City- but that’s getting off topic. For now, let’s focus on dwarves, their potential relationship to the Stone, and how their nature and civilization mirrors real-world biology.
 
To understand the role of Dwarves, and how their role has changed, we first need to understand how blood and mind are entwined in the DA universe. Time and again, we find little distinction between the two systems: both circulatory and neurological functions seem to share the same vehicle: blood. This is most obvious in the details of blood magic, in which blood provides a direct link to the minds of others. (The description of Isseya’s griffon-joining in Last Flight is a pretty graphic example, if you need one.)
 
Consequently, Dwarves actually have two original roles: they were both individual ‘neurons’ in the hive mind of the larger entity to which they belonged, and the blood of the being itself- a particularly important aspect, given the significance of blood in immune response and the need to defend the Stone against blight, red lyrium, gangue, and other “diseases”. As the theory goes, the lyrium they carry is the essence of their original, true form- their current bodies designed and crafted by June long ago to fight larger threats, golem style.
 
Dwarves as neurons:
 
This trace of lyrium has an essential purpose, though one that has waned over time as dwarven society moved ever closer to the surface and further from the Stone. This is the source of the dwarves’ vaunted stone sense: an electromagnetic charge created by their movement through the tunnels of the Deep Roads, which were once surrounded by charged (flowing = current) veins of lyrium. This magnetism not only provided an infallible sense of direction (a literal internal compass) but was also the neural charge that linked them to the larger hive mind, as Dagna seems to discover while tinkering:
 
Dagna: “There's something there. I was face-deep in a rune, and for a moment... I was tall. Really tall. And I thought -- I thought all the thoughts.” (nervous laugh)
Inquisitor: “You felt taller? How much taller?”
Dagna: “Like, mountain-tall. Or I was the mountain. But I was moving. I felt dizzy. You know what I remembered ? Watching a shaperate carve the wall of memory. Except... big. Isn't that weird ? Maybe there were fumes.”
Inquisitor: What do you mean when you say "thought all the thoughts"?
Dagna: “I don't know. As if, for a moment, I was around all my people. And my thought was all of theirs? No, no, my thought was all of our thoughts. Like parts. Ugh, words are mush. Maybe that's what the Stone feels like. Or we think it feels like. If we think it feels ? Creepy.”
 
Tearing this apart a bit: first, she feels huge and dizzy. This makes sense as the subjective experience of the Stone, since if this theory holds, it’s currently spinning beneath the ground as the planet spins.
 
Second, she’s simultaneously “around all my people” and “thinking all the thoughts” of her people- again, a fair description of connecting with the Stone’s neural network. She also mentions that the experience evoked the feeling of a shaperate carving the wall of memory, only on a huge scale. This is an important insight, as –in theory- the Wall of Memory serves to fill a function that was lost when dwarves were severed from their connection with the Earth and its Fade: a connection to the larger mind and memory of the entity of which they were a part. Cole seems to reference this disconnection in his dialogue with a dwarven Inquisitor: “No dreams with the cord cut. You sell it.” The cord is a reference to their direct connection to the Fade of the Earth or Stone. The more lyrium they mine and sell, the less surrounds the passageways they move through, and consequently the weaker this connective charge becomes.
 
Dwarves as blood cells / lymphocytes:
 
Just as they fill the role of neurons within a larger neural net, Dwarves also function as a fundamental part of the Stone’s immune system: the most common being red blood cells, though some factions may serve a more specific function. (In Last Flight, we discover that blight can be cleared from living beings by another by taking it into their own body- and critically, this only seems to work on embryonic tissue. Consider the potential parallel with how real-world phagocytes work in the body, and the odd sense of simultaneous corruption and stalwart defense Ser Evrain Abernache experienced on meeting the dwarves of Kal-Sharok. It's possible they're drawing blight from the fetal Stone by taking it into themselves.) The same Inquisitor quote from Cole describes this facet directly: “The Stone, still there, silent and reaching up for the blood that walks.” Describing dwarves as ‘blood that walks’ seems apt: their essence is a core of lyrium, the “Blood of the Earth”, encapsulated within a mobile body.
 
Bits of Solas’ dialogue with Verric offer further clues. “Dwarves are the severed arm of a once mighty hero, lying in a pool of blood, undirected, whatever skill at arms it had gone forever.” That hero, I believe, is Earth: her sacrifice necessary to bring an end –or at least a pause- in the primordial war between Order and Chaos. In this light, this “severed arm” that the dwarves represent are maternal antibodies, passed from the (now deceased) mother to the child.
 
He goes on, “Although it might twitch to give the appearance of life, it will never dream.” Here, Solas and this theory diverge. It seems likely that dwarves were individually mindless, their actions dictated by their connection to the larger being of which they were a part. One of the scrawled inscriptions in the Temple of Mythal is a possible reference to that time: "In this place we prepare to hunt the pillars of the Earth. Their workers scurry, witless, soulless. This death will be a mercy. We will make the earth blossom with their passing."
 
Naturally, one possibility for the referenced “workers” are the dwarves. In their role as immune system and the Stone’s first line of defense, they would have to be destroyed for blight to flourish unchecked. Moving back to Solas’ comment, however, it seems clear that although the Stone’s fade hasn’t developed enough to allow dreams or magic, modern dwarves are far from the ‘mindess’ drones they may once have been. Though largely disconnected from the hive mind, they are still connected to that emergent fade- they still “return to the Stone” when they die, and seem to experience ever-increasing access to emotion and other aspects as the Stone matures. Verric, an example of a dwarf with no stone sense whatsoever, is in some respects practically a dwarven “mage”- crafting entire worlds out of possibility in his novels. It's arguable that not all dreaming happens while asleep, and that the imaginative daydreaming required to write fiction borders on the same concept.
 
Returning to the idea of dwarves as immune system, it’s interesting to note that the same trace lyrium that serves as a connection to the larger being seems able to guide ‘sensitive’ dwarves to areas of infection, a slightly warped, funhouse reflection of the biochemical inflammation process that occurs in our own bodies. Gangue has an obvious disease corollary, as does the description of the dwarves’ battle with Malvernis. Red lyrium itself, in terms of its theoretical source, might be conceived of as a kind of blood (lyrium) lymphoma, perhaps pointing to why it was necessary to disconnect early dwarves from the "flow" of lyrium.
 
We find a final, slightly shaky parallel in the structure of dwarven civilization itself. To the right of this image is a map of Orzammar. To the left, a diagram of a lymph node, production site of white cell leukocytes, including critical B and T cells.
 
We also know that originally, the Deep Roads were teeming with dwarves- that passageways between thaigs weren't simply crowded, but had almost shoulder-to-shoulder traffic. A fitting image, given the theoretical equivalent.
 
Is it tenuous? Absolutely. Taken in the larger context of this theory however, it seems like a possible hint. And though I know I'm forgetting things, this is getting ridiculously long, so I'm cutting it short.
 
Anyone have other tinfoil-hat dwarf theories? @w@ We've got 24 hours to burn. Hit me with your craziest stuff.