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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 nocturnal 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.[3][4]
Physiology
Size
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)[5] 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.[6]
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.[7]
Ears
An orange tabby cat whose left ear is turned towards the back of her body.
Thirty-two individual muscles in each ear allow for a manner of directional hearing:[8] the 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. 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.[citation needed] 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.[9] 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.[10][11]
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
-
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.[12] A domestic cat's
sense of smell is about fourteen times as strong as a human's.[13] 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.[14]
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.[15][16]
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).[17] 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
- 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.[18]
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 colours.
All felines, including the big cats, have a genetic anomaly that prevents them from tasting sweetness,[14] which is a likely factor for their usual
indifference to or avoidance of fruits, berries, and other sugary foods.
Feeding and diet
Cats are obligate carnivores, meaning they must ingest the flesh of other animals to
survive. Where other carnivorous mammals like bears and dogs commonly add to their diets of meat
with fruits, berries, roots, and honey when available, by contrast all cats instinctively feed almost solely on meat.
Similarly as with its teeth, a cat's digestive tract has become specialized
over time to suit its diet, having shortened in length to only those segments of intestine best able to break down proteins and
fats from animal flesh.[19] The evolved trait severely
limits the cat's ability to properly digest, metabolize, and absorb plant-derived or synthesized nutrients, as well as certain
fatty acids. For example, cats cannot convert the pro-vitamin A abundant in plants, to make
vitamin A. Also, a number of required nutrients are not sufficiently available in plant matter to begin with; one critical
absence is taurine, a key amino sulfonic acid for eye health. Taurine deficiency can cause a
condition called macular degeneration wherein the cat's retina slowly degenerates,
eventually causing irreversible blindness.
Due to the above, most felines eat fairly little if any plantstuffs. Yet it is nevertheless quite common for a cat to
occasionally supplement its carnivorous diet with small amounts of grass, leaves, shrubs, houseplants, or other plant matter
anyway. One theory suggests this behaviour is to facilitate regurgitation if their digestion is upset; another is that it perhaps
introduces fibre or trace minerals to the diet. In this context, caution is recommended for cat owners because some houseplants
are harmful to cats. The leaves of the Easter Lily can cause permanent and
life-threatening kidney damage to cats. Philodendron are also poisonous to cats.
Cat Fancy has a full list of plants harmful to cats.[20]
As an exception to the general rule, certain domesticated cats are known to like vegetables.[21] This happenstance may inspire some vegetarian or vegan pet owners to encourage or even impose their own
dietary preferences upon their cats, often using commercially-available cat foods supplemented with chemically-synthesized taurine and other added nutrients to address nutritional shortfalls. However,
it remains arguable as to whether or not such a vegetarian diet can in fact meet a cat's dietary requirements.
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.[22][23] 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[24][23] and any suspected ingestion warrants immediate veterinary attention.[25] 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.[23] 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.[26][27]
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,[23] 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.[23] which, although they are widely used without problem, have been sometimes seen to be
fatal.[28] Antifreeze
is particularly appealing to cats, and as little as a teaspoonful can be fatal.[29]
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.[23] 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.[23]
Many houseplants are at least somewhat toxic to many species, cats included[22] and the consumption of such plants by cats is to be
avoided.
Behavior
- See also: Cat behavior and cat communication
Sociability
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 other 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.[30]
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,
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.[citation needed] 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.[31]
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
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 visual 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.[32] 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
Having evolved to survive on a meat-based diet (e.g., how the relative shortness of the
feline digestive tract prevents effective digestion of plants yet also beneficially reduces weight and thus aids in rapid
movement), cats are highly specialized for hunting. The hunt has become central to their behavior patterns, creating an affinity
for short bursts of intense exercise punctuating long periods of rest (said rests mentioned earlier as cat naps; see
Metabolism).
Much like their big cat relatives, domestic and feral cats are very effective predators.
Felines ambush and immobilize vertebrate prey using tactics similar to those of
leopards and tigers by pouncing; then they 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 it by crushing its trachea.
Domestic cat with a gift of prey for its owner.
One poorly-understood element of cat hunting behaviour, is the presentation of killed prey to their human owner(s). The
motivation is not entirely clear, but friendly bonding behaviors are thought to be often associated with such an action. It is
probable that cats in this situation expect to be praised for their symbolic contribution to the group. Some theories suggest
that cats see their owners gone for long times of the day and assume they are out hunting, as they always have plenty of food
available. Ethologist Paul Leyhausen, in an extensive study of social and predatory behavior in
domestic cats (documented in his book Cat Behavior), proposed a mechanism which explains this presenting behavior. In
simple terms, 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.
Reproduction
