Cat

This article is about domestic felines. For other uses, see Cat (disambiguation).

Cat
other images of cats
Conservation status
Template:StatusDomesticated
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Family:	Felidae
Genus:	Felis
Species:	F. silvestris
Subspecies:	F. s. catus
Trinomial name
Felis silvestris catus (Linnaeus, 1758)
Synonyms
Felis lybica invalid junior synonym Felis catus invalid junior synonym

The cat (Felis silvestris catus), also known as the domestic cat or house cat to distinguish it from other felines, is a small carnivorous species of crepuscular mammal that is often valued by humans for its companionship and its ability to hunt vermin. It has been associated with humans for at least 9,500 years, and is believed to have been domesticated in Ancient Egypt.

Physiology

Size

File:Cat anatomy diagram.svg

Diagram of the general anatomy of a male cat.

Cats typically weigh between 2.5 and 7 kg (5.5–16 pounds); however, some breeds, such as the Maine Coon, can exceed 11.3 kg (25 pounds). Some have been known to reach up to 23 kg (50 pounds) due to overfeeding. Conversely, very small cats (less than 1.8 kg / 4.0 lb) have been reported.

Skeleton

Cats have 7 cervical vertebrae like almost all mammals, 13 thoracic vertebrae (humans have 12), 7 lumbar vertebrae (humans have 5), 3 sacral vertebrae like most mammals (humans have 5 because of their bipedal posture), and, except for Manx cats, 22 or 23 caudal vertebrae (humans have 3 to 5, fused into an internal coccyx). The extra lumbar and thoracic vertebrae account for the cat's enhanced spinal mobility and flexibility, compared with humans. The caudal vertebrae form the tail, used by the cat as a counterbalance to the body during quick movements. Cats also have free-floating clavicle bones, which allows them to pass their body through any space into which they can fit their head.

Mouth

Cats have highly specialized teeth for the tearing of meat. The premolar and first molar together compose the carnassial pair on each side of the mouth, which efficiently functions to shear meat like a pair of scissors. While this is present in canids, it is highly developed in felines. The cat's tongue has sharp spines, or papillae, useful for retaining and ripping flesh from a carcass. These papillae are small backward-facing hooks that contain keratin which also assist in their grooming.

As facilitated by their oral structure, cats use a variety of vocalizations and types of body language for communication, including mewing ("meow" or "miaow"), purring, hissing, growling, squeaking, chirping, clicking, and grunting.

Ears

Thirty-two individual muscles in each ear allow for a manner of directional hearing: a cat can move each ear independently of the other. Because of this mobility, a cat can move its body in one direction and point its ears in another direction. Most cats have straight ears pointing upward. Unlike dogs, flap-eared breeds are extremely rare. (Scottish Folds are one such exceptional genetic mutation.) When angry or frightened, a cat will lay back its ears, to accompany the growling or hissing sounds it makes. Cats also turn their ears back when they are playing, or to listen to a sound coming from behind them. The angle of a cat's ears is an important clue to their mood.

Legs

Cats, like dogs, are digitigrades: they walk directly on their toes, the bones of their feet making up the lower part of the visible leg. 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 forepaw, minimizing noise and visible tracks. This also provides sure footing for their hind paws when they navigate rough terrain.

Unlike dogs and most mammals, cats walk by moving both legs on one side and then both legs on the other side. Most mammals move legs on alternate sides in sequence. Cats share this unusual gait with camels, giraffes, some horses ('pacers'), and a select few other mammals. There is no known connection between these animals which might explain this.

Like all members of family Felidae except the cheetah, cats have retractable claws. In their normal, relaxed position the claws are sheathed with the skin and fur around the 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 forefeet are typically sharper than those on the hind feet. Cats can extend their claws voluntarily on one or more paws at will. They may extend their claws in hunting or self-defense, climbing, "kneading", or for extra traction on soft surfaces (bedspreads, thick rugs, etc.). It is also possible to make a cooperative cat extend its claws by carefully pressing both the top and bottom of the paw. The curved claws may become entangled in carpet or thick fabric, which may cause injury if the cat is unable to free itself.

Most cats have five claws on their front paws, and four or five on their rear paws. Because of an ancient mutation, however, domestic cats are prone to polydactyly, and may have six or seven toes. The fifth front claw (the dewclaw) is in a more proximal position than those of the other claws. More proximally, there 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 anti-skidding device used while jumping.

Skin

Cats possess rather loose skin; this allows them to turn and confront a predator or another cat in a fight, even when it has a grip on them. This is also an advantage for veterinary purposes, as it simplifies injections. In fact, the life of cats with kidney failure can sometimes be extended for years by the regular injection of large volumes of fluid subcutaneously, which serves as an alternative to dialysis.

The particularly loose skin at the back of the neck is known as the scruff, and is the area by which a mother cat grips her kittens to carry them. As a result, cats tend to become quiet and passive when gripped there. This tendency often extends into adulthood, and can be useful when attempting to treat or move an uncooperative cat. However, since an adult cat is heavier than a kitten, a pet cat should never be carried by the scruff, but should instead have their weight supported at the rump and hind legs, and at the chest and front paws. Often (much like a small child) a cat will lie with its head and front paws over a person's shoulder, and its back legs and rump supported under the person's arm.

Senses

Main article: Cat senses

Cat senses are attuned for hunting. Cats have highly advanced hearing, eyesight, taste, and touch receptors, making the cat extremely sensitive among mammals. Cats' night vision is superior to humans although their vision in daylight is inferior. Humans and cats have a similar range of hearing on the low end of the scale, but cats can hear much higher-pitched sounds, up to 64 kHz, which is 1.6 octaves above the range of a human, and even one octave above the range of a dog. A domestic cat's sense of smell is about fourteen times as strong as a human's. To aid with navigation and sensation, cats have dozens of movable vibrissae (whiskers) over their body, especially their face. Due to a mutation in an early cat ancestor, one of two genes necessary to taste sweetness has been lost by the cat family.

Metabolism

A cat sleeping curled into a tight ball to conserve body heat.

Cats conserve energy by sleeping more than most animals, especially as they grow older. The daily duration of sleep varies, usually 12–16 hours, with 13–14 being the average. Some cats can sleep as much as 20 hours in a 24-hour period. The term cat nap refers to the cat's ability to fall asleep (lightly) for a brief period and has entered the English lexicon – someone who nods off for a few minutes is said to be "taking a cat nap".

Due to their crepuscular nature, cats are often known to enter a period of increased activity and playfulness during the evening and early morning, dubbed the "evening crazies", "night crazies", "elevenses" or "mad half-hour" by some.

The temperament of a cat can vary depending on the breed and socialization. Cats with "oriental" body types tend to be thinner and more active, while cats that have a "cobby" body type tend to be heavier and less active.

The normal body temperature of a cat is between 38 and 39 °C (101 and 102.2 °F). A cat is considered febrile (hyperthermic) if it has a temperature of 39.5 °C (103 °F) or greater, or hypothermic if less than 37.5 °C (100 °F). For comparison, humans have a normal temperature of approximately 36.8 °C (98.6 °F). A domestic cat's normal heart rate ranges from 140 to 220 beats per minute, and is largely dependent on how excited the cat is. For a cat at rest, the average heart rate should be between 150 and 180 bpm, about twice that of a human.

Genetics

Blue-eyed cats with white fur have a reputation for having greater incidence of genetic deafness.

See also: Cat coat genetics

A study by the National Cancer Institute published in the journal Science asserts that all house cats are descended from a group of self-domesticating desert wildcats Felis silvestris lybica circa 10,000 years ago, in the Near East. All wildcat subspecies can interbreed, but domestic cats are all genetically contained within F. s. lybica.

The domesticated cat and its closest wild ancestor both possess 38 chromosomes, in which over 200 heritable genetic defects have been identified, many homologous to human inborn errors. Specific metabolic defects have been identified underlying many of these feline diseases. There are several genes responsible for the hair color identified. The combination of them gives different phenotypes.

Features like hair length, lack of tail or presence of a very short tail (bobtail cat) are also determined by single alleles and modified by polygenes.

The Cat Genome Project, sponsored by the Laboratory of Genomic Diversity at the U.S. National Cancer Institute Frederick Cancer Research and Development Center in Frederick, Maryland, focuses on the development of the cat as an animal model for human hereditary disease, infectious disease, genome evolution, comparative research initiatives within the family Felidae, and forensic potential.

It is a common misconception that all white cats with blue eyes are deaf, leading to some people rejecting blue-eyed white cats as pets. This is not true, as there are many blue-eyed cats with perfect hearing. However, white cats with blue eyes do have slightly higher incidences of genetic deafness than white cats of other eye colors.

All felines, including the big cats, have a genetic anomaly that prevents them from tasting sweetness, which is a likely factor for their usual indifference to or avoidance of fruits, berries, and other sugary foods.

Feeding and diet

Cats are classified as obligate carnivores, predominantly because their physiology is geared toward efficient processing of meat, and lacks efficient processes for digesting plant matter. Similarly as with its teeth, a cat's digestive tract has become specialized over time to suit meat eating, having shortened in length only to those segments of intestine best able to break down proteins and fats from animal flesh. The trait severely limits the cat's ability properly to digest, metabolize, and absorb plant-derived nutrients, as well as certain fatty acids. For example, taurine is scarce in plants but abundant in meats. It is a key amino sulfonic acid for eye health in cats. Taurine deficiency can cause a condition called macular degeneration wherein the cat's retina slowly degenerates, eventually causing irreversible blindness.

Despite the cat's meat-oriented physiology, it is still quite common for a cat to supplement its carnivorous diet with small amounts of grass, leaves, shrubs, houseplants, or other plant matter anyway. One theory suggests this behavior helps cats regurgitate if their digestion is upset; another is that it introduces fiber or trace minerals into the diet. In this context, caution is recommended for cat owners because some houseplants are harmful to cats. For example, the leaves of the Easter Lily can cause permanent and life-threatening kidney damage to cats, and Philodendron are also poisonous to cats. Cat Fancy has a full list of plants harmful to cats.

It is unclear whether a vegetarian diet can meet a cat's dietary requirements. Nevertheless, there are several vegetarian or vegan commercially-available cat foods supplemented with chemically-synthesized taurine and other added nutrients that attempt to address nutritional shortfalls.

Additionally, cats have been known to develop a fondness for prepared human foods, normally such entrees which are rich in proteins or fats. However, a diet consisting only of human food (even if high quality meat) is unlikely to contain the balanced nutrition required by the cat. Cats normally are good self-regulators of diet; however, unlimited access to food, or excessive human-food 'treats', will often lead to the cat becoming obese, particularly if it is older or more sedentary. This may lead to several health complications, such as diabetes, especially in neutered males. Such health conditions can be prevented through diet and exercise (playing), especially for cats living exclusively indoors.

Cats can be selective eaters (which may be due in some way to the aforementioned mutation which caused their species to lose sugar-tasting ability). Unlike most mammals, cats can voluntarily starve themselves indefinitely despite being presented with palatable food, even a food which they had previously readily consumed. This can happen when the vomeronasal or Jacobson's organ becomes accustomed to a specific food, or if the cats are spoiled by their owners, in which case the cat will reject any food that does not fit the pattern it is expecting. It is also known for cats to merely become bored with their given food and decide to stop eating until they are tempted into eating again. Although it is extremely rare for a cat to deliberately starve itself to the point of injury, the sudden loss of weight can cause a fatal condition called hepatic lipidosis, a liver dysfunction which causes pathological loss of appetite and reinforces the starvation, which can lead to death within as little as 48 hours.

Some cats have a fondness for catnip, which is sensed by their olfactory systems. While they generally do not consume it, they will often roll in it, paw at it, and occasionally chew on it. The effect is usually relatively short, lasting for only a few minutes. After two hours or less, susceptible cats gain interest again. Several other species of plants (such as mint) cause this effect, to a lesser degree.

Cats can also develop pica. Pica is a condition in which animals chew or eat unusual things such as fabric, plastic or wool. In cats, this is mostly harmless as they do not digest most of it, but can be fatal or require surgical removal if a large amount of foreign material is ingested (for example, an entire sock). It tends to occur more often in Burmese, Oriental, Siamese and breeds with these in their ancestry.

Toxic sensitivity

The liver of a cat is less effective at detoxification than those of other animals, including humans and dogs; therefore exposure to many common substances considered safe for households may be dangerous to them. In general, the cat's environment should be examined for the presence of such toxins and the problem corrected or alleviated as much as possible; in addition, where sudden or prolonged serious illness without obvious cause is observed, the possibility of toxicity must be considered, and the veterinarian informed of any such substances to which the cat may have had access.

For instance, the common painkiller paracetamol or acetaminophen, sold under brand names such as Tylenol and Panadol, is extremely toxic to cats; because they naturally lack enzymes needed to digest it, even minute portions of doses safe for humans can be fatal and any suspected ingestion warrants immediate veterinary attention. Even aspirin, which is sometimes used to treat arthritis in cats, is much more toxic to them than to humans and must be administered cautiously. Similarly, application of minoxidil (Rogaine) to the skin of cats, either accidental or by well-meaning owners attempting to counter loss of fur, has sometimes proved fatal.

In addition to such obvious dangers as insecticides and weed killers, other common household substances that should be used with caution in areas where cats may be exposed to them include mothballs and other naphthalene products, as well as phenol based products often used for cleaning and disinfecting near cats' feeding areas or litter boxes, such as Pine-Sol, Dettol (Lysol), hexachlorophene, etc. which, although they are widely used without problem, have been sometimes seen to be fatal. Ethylene glycol, often used as an automotive antifreeze, is particularly appealing to cats, and as little as a teaspoonful can be fatal.

Many human foods are somewhat toxic to cats; theobromine in chocolate can cause theobromine poisoning, for instance, although few cats will eat chocolate. Toxicity in cats ingesting relatively large amounts of onions or garlic has also been reported. Even such seemingly safe items as cat food packaged in pull tab tin cans have been statistically linked to hyperthyroidism; although the connection is far from proved, suspicion has fallen on the use of bisphenol A, another phenol based product as discussed above, to seal such cans.

Many houseplants are at least somewhat toxic to many species, cats included and the consumption of such plants by cats is to be avoided.

Behavior

See also: Cat behavior and cat communication

Sociability

A yawning cat.

For cats, life in close proximity with humans (and other animals kept by humans as pets) amounts to a "symbiotic social adaptation" which has developed over thousands of years. The sort of social relationship cats have with their human keepers is hard to map onto more generalized wild cat (Felis spp.) behavior, but it is certain that the cat thinks of humans differently than it does of cats (i.e., it does not think of itself as human, nor that humans are cats). This can be seen in the difference in body and vocal language it uses with humans, when compared to how it communicates with other cats in the household, for example. Some have suggested that, psychologically, the human keeper of a cat is a sort of surrogate for the cat's mother, and that adult domestic cats live their lives in a kind of extended kittenhood.

The typical negative stereotype of a cat describes a very solitary animal, prone to opaqueness or inscrutability as well as aloofness and self-sufficiency. However, cats are not generally as asocial as that stereotype, and indeed can be quite affectionate towards their human companions, especially if they imprint on them at a very young age and are treated with consistent affection. Some breeds like the Bengal, Ragdoll, Pixie-Bob, Ocicat and Manx are known to be very social by instinct.

Regardless of the average sociability of any given cat or of cats in general, there are still any number of cats who meet or exceed the negative feline stereotype insofar as being poorly socialized. Yet with proper training and reinforcement of positive social behavior, poorly socialized cats can become more social over time. Older cats have also been reported to sometimes develop aggressiveness towards kittens, which may include biting and scratching; this type of behavior is known as Feline Asocial Aggression.

Cohabitation

One example of how house cats are naturally meant to behave is to observe feral domestic cats, which are social enough to form colonies. Each cat in a colony holds a distinct territory, with sexually active males having the largest territories, and neutered cats having the smallest. Between these territories are neutral areas where cats watch and greet one another without territorial conflicts. Outside these neutral areas, territory holders usually aggressively 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 cohabitation in colonies, cats do not have a social survival strategy, or a pack mentality. This mainly means that an individual cat takes care of all basic needs on its own (e.g., finding food, and defending itself), and thus cats are always lone hunters; they do not hunt in groups as dogs or lions do. (Of further note in this context is that it is no coincidence how cats frequently tonguebathe themselves (see Hygiene): the chemistry of their saliva, expended during their frequent grooming, appears to be a natural deodorant. Thus, a cat's cleanliness would aid in decreasing the chance a prey animal could notice the cat's presence. By contrast, dog odor is an advantage in hunting, for a dog is a pack hunter; part of the pack stations itself upwind, and its odor drives prey towards the rest of the pack stationed downwind. This requires a cooperative effort, which in turn requires communications skills. No such communications skills are required of a lone hunter.)

Fighting

Cats' acts of self defence involve arching their backs and hissing

When engaged in feline-to-feline combat for self-defense, territory, reproduction, or dominance, fighting cats make themselves appear more impressive and threatening by raising their fur and arching their backs, thus increasing their apparent size. Cats also behave this way while playing. Attacks usually comprise powerful slaps to the face and body with the forepaws as well as bites, but serious damage is rare; usually the loser runs away with little more than a few scratches to the face, and perhaps the ears. Cats will also throw themselves to the ground in a defensive posture to rake with their powerful hind legs. Normally, serious negative effects will be limited to possible infections of the scratches and bites; though these have been known to sometimes kill cats if untreated. In addition, such fighting is believed to be the primary route of transmission of feline immunodeficiency virus (FIV). Sexually active males will usually be in many fights during their lives, and often have decidedly battered faces with obvious scars and cuts to the ears and nose. Not only males will fight; females will also fight over territory or to defend their kittens, and even neutered cats will defend their (smaller) territories aggressively.

Play

Domestic cats, especially young kittens, are known for their love of play. This behaviour mimics hunting and is important in helping kittens learn to stalk, capture and kill prey. Many cats cannot resist a dangling piece of string, or a piece of rope drawn randomly and enticingly across the floor. This well known love of string is often depicted in cartoons and photographs, which show kittens or cats playing with balls of yarn. It is probably related to hunting instincts, including the common practice of kittens hunting their mother's and each other's tails. If string is ingested, however, it can become caught in the cat’s stomach or intestines, causing illness, or in extreme cases, death. Due to possible complications caused by ingesting a string, string play is sometimes replaced with a laser pointer's dot, which some cats will chase. While caution is called for, there are no documented cases of feline eye damage from a laser pointer, and the combination of precision needed and low energy involved make it a remote risk. A common compromise is to use the laser pointer to draw the cat to a prepositioned toy so the cat gets a reward at the end of the chase.

Hunting

Domestic cat presenting a bird to its owner.

Cats have evolved to be carnivores and are highly specialized for hunting. Their style of hunting uses short bursts of intense exercise punctuated long periods of rest. Much like their big cat relatives, domestic and feral cats are very effective predators. Domestic felines ambush, or pounce, and immobilize vertebrate prey using tactics similar to those of leopards and tigers. After attacking prey cats deliver a lethal neck bite with their long canine teeth that severs the prey's spinal cord, causes fatal bleeding by puncturing the carotid artery or the jugular vein, or asphyxiates the prey by crushing its trachea.

One poorly-understood element of cat hunting behaviour is the presentation of killed prey to human owner(s). Ethologist Paul Leyhausen proposed that cats adopt humans into their social group, and share excess kill with others in the group according to the local pecking order, in which humans place at or near the top. Another possibility is that presenting the kill might be a relic of a kitten feline behavior of demonstrating for its mother's approval that it has developed the necessary skill for hunting. Indoor cats will often retain their hunting instinct and deliver small household items to their owners, such as watches, pens, pencils, and other objects they can carry in their mouths. After depositing the item, they will meow to gain the attention of their owners.

Reproduction

Cats are seasonally polyestrous, which means they may have many periods of heat over the course of a year. A heat period lasts about 4 to 7 days if the female is bred; if she is not, the heat period lasts longer.

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 will reject the male. But eventually, the female will allow the male to mate. The female will give a loud yowl as the male pulls out of her. After mating, the female will give herself a thorough wash. If a male attempts to breed with her at this point, the female will attack him. Once the female is done grooming, the cycle will repeat.

The male cat's penis has spines which point backwards. Upon withdrawal of the penis, the spines rake the walls of the female's vagina, which may cause ovulation. Because this does not always occur, females are rarely impregnated by the first male with which they mate. Furthermore, cats are superfecund; that is, a female may mate with more than one male when she is in heat, meaning different kittens in a litter may have different fathers.

A kitten with eyes open for the first time.

The gestation period for cats is approximately 63–65 days. The size of a litter averages three to five kittens, with the first litter usually smaller than subsequent litters. Kittens are weaned at between six and seven weeks, and cats normally reach sexual maturity at 4–10 months (females) and to 5–7 months (males).

Cats are ready to go to new homes at about 12 weeks old (the recommended minimum age by Fédération Internationale Féline), or when they are ready to leave their mother. Cats can be surgically sterilized (spayed or castrated) as early as 6–8 weeks to limit unwanted reproduction. This surgery also prevents undesirable sex-related behavior, such as territory marking (spraying urine) in males and yowling (calling) in females. If a cat is neutered after such behavior has been learned, however, then the behavior may persist.

Hygiene

Cats are known for their fastidious cleanliness. They groom themselves by licking their fur, employing their hooked papillae and saliva. As mentioned, their saliva is a powerful cleaning agent and deodorant. Many cats also enjoy grooming humans or other cats. Sometimes the act of grooming another cat is initiated as an assertion of superior position in the pecking order of a group (dominance grooming).

Some cats occasionally regurgitate hair balls of fur that have collected in their stomachs as a result of their grooming. Longhaired cats are more prone to this than shorthaired cats. Hairballs can be prevented with certain cat foods and remedies that ease elimination of the hair and regular grooming of the coat with a comb or stiff brush. Cats expend nearly as much fluid grooming as they do urinating.

Scratching

Cats are naturally driven to periodically hook their front claws into suitable surfaces and pull backwards, in order to clean the claws and remove the worn outer sheath as well as exercise and stretch their muscles. This scratching behavior seems enjoyable to the cat, and even declawed cats will go through elaborate scratching routines with every evidence of great satisfaction, despite the total lack of results.

Fondness for heights

A cat in a tree.

Most breeds of cat have a noted fondness for settling in high places, or perching. Animal behaviorists have posited a number of explanations, the most common being that height gives the cat a better observation point, allowing it to survey its "territory" and become aware of activities of people and other pets in the area. In the wild, a higher place may serve as a concealed site from which to hunt; domestic cats are known to strike prey by pouncing from such a perch as a tree branch, as does a leopard. Height, therefore, can also give cats a sense of security and prestige.

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. This is known as the cat's "righting reflex". It 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 in most cats (safely) is around 3 feet (90 cm). Cats without a tail also have this ability, since a cat mostly moves its hind legs and relies on conservation of angular momentum to set up for landing, and the tail is in fact little used for this feat.

However, cats' fondness for high spaces can dangerously test the righting reflex. The American Society for the Prevention of Cruelty to Animals warns owners to safeguard the more dangerous perches in their homes, to avoid "high-rise syndrome", where an overconfident cat falls from an extreme height.

Ecology

Habitat

The African Wildcat (Felis sylvestris lybica), ancestor of the domestic cat, is believed to have evolved in a desert climate, as evident in the behavior common to both the domestic and wild forms. Wildcats (Felis sylvestris) are native to all continents other than Australia and Antarctica, although feral cats have become apex predators in the Australian Outback where they are menaces to wildlife. Their feces are usually dry, and cats prefer to bury them in sandy places. Urine is highly concentrated, which allows the cat to retain as much fluid as possible. They are able to remain motionless for long periods, especially when observing prey and preparing to pounce. In North Africa there are still small wildcats that are probably related closely to the ancestors of today's domesticated cat breeds.

Domestic cat enjoying heat near a window on a sunny day.

Being closely related to desert animals, cats enjoy heat and solar exposure, often sleeping in a sunny area during the heat of the day, as part of a general preference for warm temperatures. Where humans typically start to feel uncomfortable when their skin temperature gets higher than about 44.5 °C (112 °F), by contrast cats do not start to show signs of discomfort until their skin reaches about 52 °C (126 °F).

Overall, cats can easily withstand the heat and cold of a temperate climate, so long as the cold is not for extended periods. Although certain breeds such as the Norwegian Forest Cat and Maine Coon have developed heavier coats of fur than other cats, they have little resistance against moist cold (e.g., fog, rain and snow) and struggle to maintain their 39 °C (102 °F) body temperature when wet. In direct relation to that fact, most cats dislike immersion in water. One major exception is the Turkish Van breed which has an unusual fondness for water. Abyssinians are also reported to be more tolerant of water than most cats.

Impact of hunting

The domestic cat hunts and eats over a thousand species, many of them invertebrates, especially insects — many big cats will eat fewer than a hundred different species. Although theoretically big cats can kill most of these species as well, they often do not due to the relatively low nutritional content that smaller animals provide for the effort. An exception is the leopard, which commonly hunts rabbits and many other smaller animals. Even well-fed domestic cats may hunt and kill birds, mice, rats, scorpions, cockroaches, grasshoppers, and other small animals in their environment.

As a consequence of their exceptional hunting ability, cats can be quite destructive to ecosystems in which they are not native, where local species have not had time to adapt to feline introduction. In some cases, cats have contributed to or caused extinctions — for example, see the case of the Stephens Island Wren. Due to their hunting behavior, in many countries feral cats are considered pests. Domestic cats are occasionally also required to have contained cat runs or to be kept inside entirely, as they can be hazardous to locally endangered bird species. For instance, various municipalities in Australia have enacted such legislation. In some localities, owners fit their cat with a bell in order to warn prey of its approach (although some cats may figure out how and when the bell works, thereby learning more careful movements to avoid the ringing).

House cats

Domestication

In 2004, a grave was excavated in Cyprus that 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.

In captivity, indoor cats typically live 14 to 20 years, though the oldest-known cat lived to age 36. Domesticated cats tend to live longer if they are not permitted to go outdoors (reducing the risk of injury from fights or accidents and exposure to diseases) and if they are neutered. Some such benefits are: castrated male cats cannot develop testicular cancer, spayed female cats cannot develop ovarian cancer, and both have a reduced risk of mammary cancer.

Like some other domesticated animals, cats live in a mutualistic arrangement with humans. It is believed that the benefit of removing rats and mice from humans' food stores outweighed the trouble of extending the protection of a human settlement to a formerly wild animal, almost certainly for humans who had adopted a farming economy. Unlike the dog, which also hunts and kills rodents, the cat does not eat grains, fruits, or vegetables. A cat that is good at hunting rodents is referred to as a mouser.

In modern rural areas, farms often have dozens of semi-feral cats. Hunting in the barns and the fields, they kill and eat rodents that would otherwise spoil large parts of the grain crop. Many pet cats successfully hunt and kill rabbits, rodents, birds, lizards, frogs, fish, and large insects by instinct, but might not eat their prey. They may even present their kills, dead or maimed, to their humans, perhaps expecting them to praise or reward them, or possibly even to complete the kill and eat the mouse.

In modern urban areas, some people find feral and free-roaming pet cats annoying and intrusive. Unaltered cats can engage in persistent nighttime calling (termed caterwauling) and defecation or "marking" of private property. Indoor confinement of pets and TNR (trap, neuter, return) programs for feral cats can help; some people also use cat deterrents to discourage cats from entering their property.

Interaction with humans

Human attitudes toward cats vary widely. Some people keep cats for casual companionship as pets. Others go to great lengths to pamper their cats, sometimes treating them as if they were children. Cats are also bred and shown as registered pedigree pets, in a hobby known as the cat fancy.

When a cat bonds with its human guardian, the cat may, at times, display behaviors similar to that of a human. Such behavior may include a trip to the litter box before bedtime or snuggling up close to its companion in bed or on the sofa. Other such behavior includes mimicking sounds of the owner or using certain sounds the cat picks up from the human; sounds representing specific needs of the cat, which the owner would recognize, such as a specific tone of meow along with eye contact that may represent "I'm hungry." The cat may also be capable of learning to communicate with the human using non-spoken language or body language such as rubbing for affection (confirmation), facial expressions and making eye contact with the owner if something needs to be addressed (e.g., finding a bug crawling on the floor for the owner to get rid of).

Because of their small size, domesticated house cats pose almost no danger to adult humans — the main hazard is the possibility of infection (e.g., cat scratch disease, or, rarely, rabies) from a cat bite or scratch. Cats can also potentially inflict severe scratches or puncture an eye, though this is quite rare (although dogs have been known to be blinded by cats in fights, where the cat specifically and accurately targeted the eyes of the larger animal).

Cats rarely if ever injure children, although their claws are sharp and their play can be fairly rough. There is an old wives tale that cats can 'suck the breath' from babies, sometimes it is held that the cat is looking for milk. This is false. Still, keeping cats off of cots is probably wise, as a cat could theoretically accidentally smother a child by lying across its face. Cats also seem to have a behaviour where they will sleep right next to an ill person who is running a temperature.

Allergens

Allergic reactions to cat dander and/or cat saliva inspire one of the most common reasons people cite for disliking cats. Some humans who are allergic to cats—typically manifested by hay fever, asthma or a skin rash—quickly acclimate themselves to a particular animal and live comfortably in the same house with it, while retaining an allergy to cats in general. Many humans find the rewards of cat companionship outweigh the discomfort and problems associated with these allergens. Some cope with the problem by taking prescription allergy medicine, along with bathing their cats frequently (weekly bathing will eliminate about 90% of the cat dander present in the environment).

Trainability

Some owners seek to train their cat in performing tricks commonly exhibited by dogs, such as jumping, though this is rare. Individual cats have been known to learn to manipulate simple mechanisms, like sink faucets, by themselves or after prompting/encouraging. With effort and patience on the part of an owner, the average cat can usually be trained to at least obey simple commands such as "get off the furniture" or "come to dinner". In general though, the seeming intractability of the ordinary house cat to training has long inspired the simile "like herding cats", as a general expression to describe any situation with a stubborn or uncooperative learner.

Indoor scratching

As mentioned, cats are naturally driven to periodically hook their front claws into suitable surfaces and pull backwards, in order to clean the claws. Indoor cats benefit from being provided with a scratching post so that they are less likely to use carpet or furniture which they can easily ruin. Commercial scratching posts typically are covered in carpeting or upholstery, but some authorities advise against this practice, as not making it clear to the cat which surfaces are permissible and which are not; they suggest using a plain wooden surface, or reversing the carpeting on the posts so that the rougher texture of the carpet backing is a more attractive alternative to the cat than the floor covering. Scratching posts made of sisal rope or corrugated cardboard are also commonly found. Some indoor cats, however, especially those that were taken as kittens from feral colonies, may not understand the concept of a scratching post, and as a result will ignore it.

Close-up of a cat's claw, with the quick clearly visible.

Although scratching can serve cats to keep their claws from growing excessively long, their nails can be trimmed if necessary with a small nail trimmer designed for humans, or a small pair of electrician's diagonal cutting pliers, or a guillotine type cutter specifically designed for animal nail trimming. Care must always be taken to avoid cutting the quick of the claw, analogous to cutting into the tip of a finger and equally painful and bloody. The position of the quick can be easily seen through the translucent nail of a cat with light colored claws but not in cats with dark colored nails, who therefore require carefully trimming of only small amounts from the nails.

Declawing

Main article: Onychectomy

Declawing is a major surgery known as onychectomy, performed under anesthesia, which removes the tip of each digit (from the first knuckle out) of the cat's forepaws (and rarely the hind paws). The primary reason for declawing cats is to prevent them from damaging furniture; in the United States, some landlords may require that tenants' cats be declawed. Rarely, vicious cats, cats that frequently fight with other pets, or cats that are too efficient at predation of songbirds etc. are declawed. This controversial procedure is uncommon outside of North America, and is prohibited by animal cruelty laws in many countries worldwide.

An alternative to declawing is the application of blunt, vinyl nail caps that are affixed to the claws with nontoxic glue, requiring periodic replacement when the cat sheds its claw sheaths (about every four to six weeks). However, the cat will still experience difficulties because the capped nails are not as effective as claws.

Waste

Indoor cats are usually provided with a litter box containing litter, typically bentonite, but sometimes other absorbent material such as shredded paper or wood chips, or sometimes sand or similar material. This arrangement serves the same purpose as a toilet for humans. It should be cleaned daily and changed often, depending on the number of cats in a household and the type of litter; if it is not kept clean, a cat may be fastidious enough to find other locations in the house for urination or defecation. This may also happen for other reasons; for instance, if a cat becomes constipated and defecation is uncomfortable, it may associate the discomfort with the litter box and avoid it in favor of another location. A litterbox is recommended for indoor-outdoor cats as well.

Daily attention to the litter box also serves as a monitor of the cat's health. Numerous variations on litter and litter box design exist, including some which automatically sift the litter after each use. Bentonite or clumping litter is a variation which absorbs urine into clumps which can be sifted out along with feces, and thus stays cleaner longer with regular sifting, but has sometimes been reported to cause health problems in some cats.

Toilet-trained house cat.

Litterboxes may pose a risk of toxoplasmosis transmission to susceptible pregnant women and immuno-compromised individuals. Most indoor-only cats would not normally be exposed to the disease and are not usually carriers. Transmission risk may be reduced by daily litterbox cleaning by someone other than the susceptible individual.

Some cats can be toilet trained, eliminating the litterbox and its attendant expense, unpleasant odor, and the need to use landfill space for disposal. Training may involve two or three weeks of incremental moves, such as moving and elevating the litterbox until it is near the toilet. For a short time, an adapter, such as a bowl or small box, may be used to suspend the litter above the toilet bowl but under the toilet seat. Several kits and other aids are marketed to help toilet-train cats. When training is complete, the cat uses the toilet by perching over the bowl.

Domesticated varieties

The list of cat breeds is quite large: most cat registries actually recognize between 30 and 40 breeds of cats, and several more are in development, with one or more new breeds being recognized each year on average, having distinct features and heritage. The owners and breeders of show cats compete to see whose animal bears the closest resemblance to the "ideal" definition & standard of the breed (see selective breeding). Because of common crossbreeding in populated areas, many cats are simply identified as belonging to the homogeneous breeds of domestic longhair and domestic shorthair, depending on their type of fur. In the United Kingdom and Australia, non-purebred cats are referred in slang as moggies (derived from "Maggie", short for Margaret, reputed to have been a common name for cows and calves in 18th century England and latter applied to housecats during the Victorian era). In the United States, a non-purebred cat is sometimes referred to in slang as a barn or alley cat, even if it is not a stray. Cats come in a variety of colors and patterns. These are physical properties and should not be confused with a breed of cat. Some original cat breeds that have a distinct phenotype that is the main type occurring naturally as the dominant domesticated cat type in their region of origin are sometimes considered as subspecies and also have received names as such in nomenclature, although this is not supported by feline biologists. Some of these cat breeds are:

• F. catus anura - the Manx
• F. catus siamensis - the Siamese
• F. catus cartusenensis - the Chartreux
• F. catus angorensis - the Turkish Angora

Coat patterns

Cat with a van pattern.

Cat coat genetics can produce a variety of coat patterns. Some of the most common are:

Bicolor, Tuxedo and Van

This pattern varies between the tuxedo cat which is mostly black with a white chest, and possibly markings on the face and paws/legs, all the way to the Van pattern (so named after the Lake Van area in Turkey, which gave rise to the Turkish Van breed), where the only colored parts of the cat are the tail (usually including the base of the tail proper), and the top of the head (often including the ears). There are several other terms for amounts of white between these two extremes, such as Harlequin or jellicle cat. Bicolor cats can have as their primary (non-white) color black, red, any dilution thereof and tortoiseshell (see below for definition).

Mackerel tabby cat, showing the characteristic "M" on its forehead.

Tabby cat

Striped, with a variety of patterns. The classic "blotched" tabby (or "marbled") pattern is the most common and consists of butterflies and bullseyes. The "mackerel" or "striped" tabby is a series of vertical stripes down the cat's side (resembling the fish). This pattern broken into spots is referred to as a "spotted" tabby. Finally, the tabby markings may look like a series of ticks on the fur, thus the "ticked" tabby, which is almost exclusively associated with the Abyssinian breed of cats. The worldwide evolution of the cat means that certain types of tabby are associated with certain countries; for instance, blotched tabbies are quite rare outside NW Europe, where they are the most common type.

File:Curly calico2.gif

Female tortoiseshell-and-white cat.

Tortoiseshell and Calico

This cat is also known as a Calimanco cat or Clouded Tiger cat, and by the nickname "tortie". In the cat fancy, a tortoiseshell cat is randomly patched over with red (or its dilute form, cream) and black (or its dilute blue) mottled throughout the coat. Additionally, the cat may have white spots in its fur, which make it a "tortoiseshell and white" cat or, if there is a significant amount of white in the fur and the red and black colors form a patchwork rather than a mottled aspect, the cat will be called a "calico". All calicos are tortoiseshell (as they carry both black and red), but not all tortoiseshells are calicos (which requires a significant amount of white in the fur and patching rather than mottling of the colors). The calico is also sometimes called a "tricolor cat". The Japanese refer to this pattern as mi-ke (meaning "triple fur"), while the Dutch call these cats lapjeskat (meaning "patches cat"). A true tricolor must consist of three colors: a reddish color, dark or light; white; and one other color, typically a brown, black or blue, as described by American breeder Barbara French, writing for the Cat Fanciers community. Both tortoiseshell and calico cats are typically female because the coat pattern is the result of differential X chromosome inactivation in females (which, as with all normal female mammals, have two X chromosomes). Those male tortoiseshells that are created are usually sterile; conversely, cats where the overall color is ginger (orange) are commonly male (roughly in a 3:1 ratio). In a litter sired by a ginger tom, the females will be tortoiseshell or ginger. See "Tortoiseshell and Tricolor cats" for an extensive genetic explanation for tricolor cats, and detailing the possible combinations of coloring.

Siamese cat, classical colorpoint pattern.

Colorpoint

The colorpoint pattern is most commonly associated with Siamese cats, but may also appear in any domesticated cat. A colorpointed cat has dark colors on the face, ears, feet, and tail, with a lighter version of the same color on the rest of the body, and possibly some white. The exact name of the colorpoint pattern depends on the actual color, so there are seal points (dark brown), chocolate points (warm lighter brown), blue points (dark gray), lilac points (silvery gray-pink), flame points (orange), and tortie (tortoiseshell mottling) points, among others. This pattern is the result of a temperature sensitive mutation in one of the enzymes in the metabolic pathway from tryptophan to pigment, such as melanin; thus, little or no pigment is produced except in the extremities or "points", where the skin is slightly cooler. For this reason, colorpointed cats tend to darken with age as bodily temperature drops; also, the fur over a significant injury may sometimes darken or lighten as a result of temperature change.

The tryptophan pathway also produces neurotransmitters, thus mutations in the early parts of that pathway may affect not only pigment, but also neurological development. This results in a higher frequency of cross-eyes among colorpointed cats, as well as the high frequency of deafness in white cats and the high frequency of cross-eyes in white tigers. (This is not related to albinism).

Body types

Cats can also come in several body types, ranging between two extremes:

Oriental

Not a specific breed, but any cat with an elongated slender build, almond-shaped eyes, long nose, large ears (the Siamese and Oriental Shorthair breeds are examples of this).

Cobby

Any cat with a short, muscular, compact build, roundish eyes, short nose, and small ears. Persian cats and Exotic cats are two prime examples of such a body type.

Feral cats

Main article: Feral cat

Feral Cats at Kona, Hawaii.

Feral cats may live alone, but most are found in large groups called feral colonies with communal nurseries, depending on resource availability. Most abandoned cats probably have little alternative to joining a feral colony. The average lifespan of such feral cats is much shorter than a domestic house cat, which can live 16 years or more. Urban areas in the developed world are not friendly, nor adapted environments for cats; most domesticated cats are descended from cats in desert climates and were distributed throughout the world by humans. Nevertheless, some feral cat colonies are found in large cities such as around the Colosseum and Forum Romanum in Rome. The Roman cats are not truly feral because they are partly fed and vetted by the local authority. Because cats are adaptable those in residential areas know that if they are friendly to humans they need not worry about food or shelter. Some urban "stray" cats have many houses/humans to support them.

Although cats are adaptable, feral felines are unable to thrive in extreme cold and heat, and with a very high protein requirement, few find adequate nutrition on their own in cities. They are often killed by dogs, coyotes, and automobiles. However, there are thousands of volunteers and organizations that trap these unadoptable feral felines, neutering them, immunize the cats against rabies and feline leukemia, and treat them with long-lasting flea products. Before release back into their feral colonies, the attending veterinarian often nips the tip off one ear to mark the feral as neutered and inoculated, since these cats will more than likely find themselves trapped again. Volunteers continue to feed and give care to these cats throughout their lives, and not only is their lifespan greatly increased, but behavior and nuisance problems, due to competition for food, are also greatly reduced. In time, if an entire colony is successfully neutered, no additional kittens are born and the feral colony disappears.

Environmental effects

Trapped Feral cat

The environmental effects of feral cats vary greatly. In the Northern Hemisphere most landmasses have fauna adapted to wildcat (Felis sylvestris) species and other placental mammal predators. The potential for environmental damage due to feral cats is arguably low, unless cat populations are very high, or the region supports unusually vulnerable native wildlife species. Feral cats are thought to be a major predator of Hawaiian coastal and forest habitats, and are one species among many responsible for the decline of endemic forest bird species as well as seabirds like the Wedge-tailed Shearwater. In one study of 56 cats' feces, the remains of 44 birds were found, 40 of which were endemic species. Fauna on islands of all sizes that are unfamiliar with felines as predators are particularly vulnerable to feral cats.

In the Southern Hemisphere there are many landmasses including Australia where cat species have never been native, and other placental mammalian predators were rare or absent. Native species there tend to be more ecologically vulnerable and behaviorally "naive" to predation by feral cats. Feral cats have had serious affects on these wildlife species and have played a leading role in the endangerment and extinction of many of them. In Australia a large quantity of native birds, lizards and small marsupials are taken every year by feral cats, and feral cats have played a role in driving some small marsupial species to extinction. Some organizations in Australia are now going to effort of creating fenced islands of habitat for endangered species that are free of feral cats and foxes.

Ethical and humane concerns over feral cats

There are two divergent views about the relationship of cats with the natural environment. The first argues that the environmental impact of feral cat programs and of indoor/outdoor cats is a subject of debate. Part of this stems from humane concern for the cats, and part stems from concerns about cat predation on endangered species. Nearly all studies agree that abandoned animals lead hard lives. The amount of ecological damage done by indoor/outdoor cats depends on local conditions. As suggested above, the most severe effect occurs to island ecologies. Environmental concerns may be minimal in most of the UK where cats are an established species and few to none of the local prey species are endangered. Pet owners can contact veterinarians, ecological organizations, and universities for opinions about whether local conditions are suitable for outdoor cats. Additional concerns include potential dangers from larger predators and infectious diseases. Coyotes kill large numbers of housecats in the Southwestern United States, even in urban zones. FELV (feline leukemia), FIV (feline immunodeficiency virus), or rabies may be present in the area. If faced with conflicting evidence, the safe choice is to keep a cat indoors. Experts recommend a gradual transition to indoor life for cats who are accustomed to going outside.

Cats present a risk of overpopulation, as well. According to the Humane Society of the United States, 3–4 million cats and dogs are euthanized each year in the United States and many more are confined to cages in shelters because there are significantly more animals being born than there are homes. Neutering pets helps keep the overpopulation down. A study in 1992 found that in the USA, 12,893 (29.4%) of pets, 26.9% of dogs and 32.6% of cats were sterilized. Local humane societies, SPCAs, and other animal protection organizations urge people to neuter their pets and to adopt from shelters instead of purchasing elsewhere.

Etymology and taxonomic history

Scientific classification

The domesticated cat was previously classified as Felis catus by Carolus Linnaeus in his Systema Naturae of 1758. Johann Christian Daniel von Schreber named the Wildcat Felis silvestris in 1775. However, in opinion 2027 (published in Volume 60, Part 1 of the Bulletin of Zoological Nomenclature, March 31, 2003) the International Commission on Zoological Nomenclature "conserved the usage of 17 specific names based on wild species, which are predated by or contemporary with those based on domestic forms", thus confirming F. silvestris for the Wildcat and F. silvestris catus for its domesticated cousin.

Johann Christian Polycarp Erxleben classified the domesticated cat as Felis domesticus in his Anfangsgründe der Naturlehre and Systema regni animalis of 1777. This name, and its variants Felis catus domesticus and Felis silvestris domesticus, are often seen, but they are not valid scientific names under the rules of the International Code of Zoological Nomenclature.

Nomenclature

A group of cats is referred to as a clowder, a male cat is called a tom (or a gib, if neutered), and a female is called a queen. The male progenitor of a cat, especially a pedigreed cat, is its sire, and its female progenitor is its dam. An immature cat is called a kitten (which is also an alternative name for young rats, rabbits, hedgehogs, beavers, squirrels and skunks). In medieval Britain, the word kitten was interchangeable with the word catling. A cat whose ancestry is formally registered is called a pedigreed cat, purebred cat, or a show cat (although not all show cats are pedigreed or purebred). In strict terms, a purebred cat is one whose ancestry contains only individuals of the same breed. A pedigreed cat is one whose ancestry is recorded, but may have ancestors of different breeds (almost exclusively new breeds; cat registries are very strict about which breeds can be mated together). Cats of unrecorded mixed ancestry are referred to as domestic longhairs and domestic shorthairs or commonly as random-bred, moggies, mongrels, mutt-cats or alley cats. The ratio of pedigree/purebred cats to random-bred cats varies from country to country. However, generally speaking, purebreds are less than ten percent of the total Feline population.

Etymology

The word cat derives from Old English catt, which belongs to a group of related words in European languages, including Welsh cath, Spanish gato, Basque katu, Byzantine Greek kátia, Old Irish cat, German Katze, and Old Church Slavonic kotka. The ultimate source of all these terms is Late Latin catus, cattus, catta "domestic cat", as opposed to feles "European wildcat". It is unclear whether the Greek or the Latin came first, but they were undoubtedly borrowed from an Afro-Asiatic language akin to Nubian kadís and Berber kaddîska, both meaning "wildcat". This term was either cognate with or borrowed from Late Egyptian čaus "jungle cat, African wildcat" (later giving Coptic šau "tomcat"), itself from earlier Egyptian tešau "female cat" (vs. miew "tomcat").

The term puss (as in pussycat) may come from Dutch poes or from Low German Puuskatte, dialectal Swedish kattepus, or Norwegian puse, pusekat, all of which primarily denote a woman and, by extension, a female cat.

History and mythology

Egyptian sculpture at the Louvre.

Main articles: History of cats and Cats in ancient Egypt

Cats have been kept by humans since at least ancient Egypt, where the mythical cat Bast was goddess of the home, the domesticated cat, protector of the fields and home from vermin infestations, and sometimes took on the warlike aspect of a lioness. The first domesticated cats may have saved early Egyptians from many rodent infestations and likewise, Bast developed from the adoration for her feline companions. She was the daughter of the sun god Ra and played significant role in Ancient Egyptian religion. It has been speculated that cats resident in Kenya's Islands in the Lamu Archipelago may be the last living direct descendants of the cats of ancient Egypt.

Several ancient religions believed that cats are exalted souls, companions or guides for humans, that they are all-knowing but are mute so they cannot influence decisions made by humans. In Japan, the Maneki Neko is a cat that is a symbol of "good fortune". While in Islam there is not a sacred species, it is said by some writers that Muhammad had a favorite cat, Muezza. It is said he loved cats so much that "he would do without his cloak rather than disturb one that was sleeping on it".

Nine Lives

It is common lore that cats have nine lives. It is a tribute to their perceived durability, their occasional apparent lack of instinct for self-preservation, and their seeming ability to survive falls that would be fatal to other animals.

This disregard for safety is common in animals of this size and smaller. A cat is about the largest that can fall from any height with a significant chance of survival. Because the surface area to volume ratio is large the terminal velocity is fairly small. Their bones are less calcified than in larger animals so they can elastically absorb more energy (tougher/more "rubbery").

See also

• Cat body type genetic mutations
• Cat breed
• Cat Fanciers' Association
• Cat meat
• Cat types
• Feline ethology
• List of cat breeds
• List of historical cats
• List of fictional cats
• Sex organ of cat
• Cat pheromone
• Cat intelligence

External links

Anatomy

• High-Resolution Images of the Cat Brain

Articles

• Predatory Behavior of Cats Explained (with pictures) on Alberta Stars
• Choosing a cat - article at Citizendium
• Catpert. The Cat Expert - Cat articles
• Cat behavior explained

Veterinary related

• American Association of Feline Practitioners
• Cat Genome Project at the US The National Cancer Institute
• Cornell Feline Health Center
• Feline Medical & Behaviour Database (large number of short articles)
• Information about the third eyelid of cats, and the problem of Kertao, or "dry eye".
• Onions are Toxic to Cats
• Feline Behavior Guidelines An AAFP publication
• Cat Vaccination and Health Care Schedule