Cats
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Wikipedia-Article "Cats"
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| Felis silvestris catus (Linnaeus, 1758) |
- This article is about the domestic cat. For alternative meanings see cat (disambiguation).
The cat, also called the domestic cat or house cat, is a small feline carnivorous mammal of the subspecies Felis silvestris catus. Its most immediate, pre-domestication ancestor is the African wild cat, Felis silvestris lybica. The cat has been living in close association with humans for at least 3,500 years; the Ancient Egyptians routinely used cats to keep mice and other rodents away from their grain (and also believed that cats were sacred). The history of the domestic cat may stretch back even further, as 8,000-year-old bones of humans and cats were found buried together on the island of Cyprus[3].
A group of cats is referred to as a clowder, while a male cat is called a tom, and a female is called a queen or quean. An immature cat is called a kitten (which is also an alternate name for young rats, rabbits, hedgehogs, beavers, and squirrels). A cat whose ancestry is formally registered is called a purebred cat, a pedigree cat, or a show cat (although not all show cats are pedigree or purebred). In strict terms, a purebred cat is one whose ancestry contains only individuals of the same breed. A pedigree cat is one whose ancestry is recorded, but may have ancestors of different breeds.
Purebreds are less than one percent of the total feline population; cats of 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.
There are dozens of breeds of domestic cats, some hairless or tailless, and they exist in a variety of different colors including multicolored. They are skilled predators and have been known to hunt over one thousand different species for food. They are also intelligent animals: some are able to manipulate simple mechanisms such as lever-handled doors and flush toilets. They communicate by calling ("meow"/"miaou"), purring, hissing, and gesturing. Because the domestication of the cat is relatively recent, cats may also still live effectively in the wild, often forming small colonies. The cat's association with humans leads it to figure prominently in the mythology and legends of several cultures, including the ancient Egyptians, Vikings, and Chinese.
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Characteristics
Physical
Cats typically weigh between 2.5 and 7 kg (5.5–16 lb); 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 lb), due to overfeeding. This is very unhealthy for the cat, and should be prevented through exercise (playing) and diet, especially for cats living exclusively indoors.
In captivity, indoor cats typically live 15 to 20 years, though the oldest-known cat lived to age 36.[4] Domestic cats tend to live longer if they are not permitted to go outdoors (reducing the risk of injury from fights or accidents) and if they are spayed or neutered. Spaying and neutering a cat also decreases the risk of testicular and ovarian cancer, and female cats spayed before their first heat or litter benefit from reduced risk of mammary cancer.[5] Feral cats living in modern urban environments often live only two years, or less. Feral cats in maintained colonies can live much longer; the British Cat Action Trust reported a 19-year-old feral female. The oldest feral cat was Mark who was maintained by the British charity Cats Protection and who reached 26 years of age.
Thirty-two individual muscles in the ear allow for a manner of directional hearing; [6] the cat can move each ear independently of the other. Thus a cat can move its body in one direction and point its ears in quite another direction (such as pointing backward toward its owner). 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 its ears back, to accompany the growling or hissing sounds it makes. Cats conserve energy by sleeping more than most animals, especially as they grow older. Daily durations of sleep are various, 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 for a brief period; someone who nods off for a few minutes is said to be "taking a cat nap".
A cat's temperament can vary depending on the breed and socialization. Shorter haired cats tend to be skinnier and more active, while cats with longer hair 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).[7] A cat is considered febrile if it has a temperature of 39.5 °C (103 °F) or greater, or hypothermic if less than 37.5 °C (100 °F). Comparatively, humans have a normal temperature of approximately 37 °C (97 to 100 °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, depending upon level of activity.
A popular belief holds that cats always land on their feet. They do usually, but not always. During a fall, a cat can reflexively twist its body and right itself using its acute sense of balance and flexibility. [8] It always rights itself in the same way, provided it has the time to do so during a fall. Certain breeds that don't have a tail are a notable exception, since a cat moves its tail and relies on conservation of angular momentum to set up for landing.
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. They are capable of walking very precisely, placing each hind paw directly in the print of the corresponding forepaw, minimising noise and visible tracks.
Senses
Many zoologists believe that the feline is the most sensual of all mammals. While its smell and hearing may not be as keen as, say, those of a mouse, its highly advanced eyesight and superior (by human standards) aural (sound) and olfactory (smell) senses combine with highly evolved taste and touch receptors to make the cat arguably the most sensitive of any mammal. Measuring the senses of any animal can be difficult, because there is usually no explicit communication (e.g., reading aloud the letters of a Snellen chart) between the subject and the tester. However, testing indicates that a cat's vision is superior at night in comparison to humans, and inferior in daylight. Cats, like dogs, have a tapetum lucidum that reflects extra light to the retina. While this enhances the ability to see in low light, it appears to reduce net visual acuity, thus detracting when light is abundant. In very bright light, the slit-like iris closes very narrowly over the eye, reducing the amount of light on the sensitive retina, and improving depth of field. The tapetum and other mechanisms give the cat a minimum light detection threshold up to 7 times lower than that of humans. Variation in color of cats' eyes in flash photographs is largely due to the interaction of the flash with the tapetum.
Average cats have a visual field of view estimated at 200°, versus 180° in humans, with a binocular field (overlap in the images from each eye) narrower than that of humans. As with most predators, their eyes face forward, affording depth perception at the expense of field of view. Field of view is largely dependent upon the placement of the eyes, but may also be related to the eye's construction. Instead of the fovea which gives humans sharp central vision, cats have a central band known as the visual streak. Cats can apparently differentiate among colors, especially at close range, but without appreciable subtlety.
Cats have a third eyelid, the nictitating membrane, which is a thin cover that closes from the side and appears when the cat's eyelid opens. This membrane partially closes if the cat is sick; although in a sleepy, content cat this membrane is often visible. If a cat chronically shows the third eyelid, it should be taken to a veterinarian.
Humans and cats have a similar range of hearing on the low end of the scale, but cats can hear much higher-pitched sounds, even better than dogs. Cats can hear 2 octaves higher than humans, and one-half octave higher than dogs. When listening for something, a cat's ears will swivel in that direction; a cat's ear flaps (pinnae) can independently point backwards as well as forwards and sideways to pinpoint the source of the sound. Cats can judge within three inches (7.5 cm) the location of a sound being made one yard (approximately one meter) away.
A domestic cat's sense of smell is about 14 times stronger than a human's. Cats have twice as many smell-sensitive cells in their noses as people do, which means they can smell things we are not even aware of. Cats also have a scent organ in the roof of their mouths called the vomeronasal, or Jacobson's, organ. When a cat wrinkles its muzzle, lowers its chin, and lets its tongue hang a bit, it is opening the passage to the vomeronasal. This is called gaping. Gaping is the equivalent of the Flehmen response in other animals, such as dogs and horses.
Cats generally have about a dozen whiskers in four rows on each upper lip, a few on each cheek, tufts over the eyes and bristles on the chin. Whiskers may also be found on the cat's "elbows." The Sphynx (a nearly hairless breed) may have full length, short, or no whiskers at all.
Whiskers (technically called vibrissae) can aid with navigation and sensation. Whiskers may detect very small shifts in air currents, enabling a cat to know it is near obstructions without actually seeing them. The upper two rows of whiskers can move independently from the lower two rows for even more precise measuring.
It is thought that a cat may choose to rely on the whiskers in dim light where fully dilating the pupils would reduce its ability to focus on close objects. The whiskers also spread out roughly as wide as the cat's body making it able to judge if it can fit through an opening.
Whiskers are also an indication of the cat's attitude. Whiskers point forward when the cat is inquisitive and friendly, and lie flat on the face when the cat is being defensive or aggressive.
An oddity about cat's sense of taste is, according to National Geographic (December 8), cats can not taste sugary foods due to a faulty sweet receptor gene. Some scientists believe this is related to the cat's diet being naturally high in protein, though it is unclear whether it the cause or the result of it.
Communication
The unique sound a small cat makes is written onomatopoeically as "meow" in American English; "meow" or "miaow" in British English; "miaou" or "miaw" in French; "miao" in Mandarin Chinese and Italian; "miau" in German, Spanish, Finnish, Lithuanian, Polish and Portuguese; "mjäu" in Estonian; "mowa'a" in Arabic; "nyaa" or "nyan" in Japanese; "meong" or "ngeong" in Bahasa Indonesia; "ngiau" in Malay; "yaong" or "nyaong" in Korean; and various ways in other languages. The sound of an increasingly annoyed cat is transcribed in James Joyce's Ulysses as "mkgnao", "mrkgnao" and "mrkrgnao" [9]. The cat's pronunciation of this call varies significantly depending on meaning. Usually cats call out to indicate pain, request human attention (to be fed or played with, for example), or as a greeting. Some cats are very vocal, and others rarely call out. Cats are capable of about 100 different vocalisations, compared to about 10 for dogs.
A kitten's call first starts out as a high-pitched squeak-like sound when very young, and then deepens over time. Some cats, however, do not exercise their voices a lot, so their call may remain similar to that of a kitten through adulthood.
Cats can also produce a purring noise that typically indicates that the cat is happy, but also can mean that it feels distressed. Cats purr among other cats—for example, when a mother meets her kittens. Until recently, there were many competing theories to explain how cats purr, including vibration of the cat's false vocal chords when inhaling and exhaling, the sound of blood hitting the aorta, vibration of the hyoid apparatus, or resonation directly in the lungs. Currently, though, it is believed that purring is a result of rhythmic impulses to the cat's larynx.
It is possible for a cat to call out and purr simultaneously, although this is typical only in very vocal cats. In addition to purring, happy cats may blink slowly or partially close their eyes to break any possible stares and communicate their ease in the situation. However, purring may also be a way for the cat to calm itself down. For example, cats have been known to purr when hurt.
Most cats growl or hiss when angered or in danger. Some may engage in nipping behavior or batting with their paws, either with claws extended or retracted. With cats who are improperly socialised and do not know their own strength, this can result in inadvertent damage to human skin. Cat scratches can easily become infected, and in extreme cases can result in cat scratch fever.
Cats are also known to make chirping noises when observing prey, or as a means of expressing interest in an object to nearby humans. When directed at out-of-reach prey, it is unknown whether this is a threatening sound, an expression of frustration, or an attempt to replicate a birdcall (or replicate the call of a bird's prey, for example a cicada). Since this feline expression often involves a mouth movement similar to the one they would use to kill their prey (their "killing bite"), they may be trying to practice this mouth movement in anticipation.
When passing solid waste, cats, like many types of predators, release from anal glands a small amount of liquid that scents their feces, to mark their territory. These scent-producing anal sacs are found in all predators; those of the skunk are used for self-defense, for example. During moments of excitement or other strong emotions, a cat's anal sac may discharge, releasing a foul-smelling brown liquid. Anal irritation, possibly shown by the cat rubbing its bottom on the floor and frequent licking of the area, can be a sign that the cat's anal sacs are not being emptied when waste passes [10]. Although this condition can be treated through the addition of a small amount of bran to each meal, it may require veterinary attention. Shorthair cats are more prone to this problem.
Cats will twitch the tips of their tails when hunting or angry, while larger twitching indicates displeasure. A tail held high is a sign of happiness, while half-raised shows less pleasure, and unhappiness is indicated with a tail held low. A scared cat may puff up its tail and the hair along its back to increase its apparent size. Touching noses is a friendly greeting for cats, while a lowered head is a sign of submission.
When cats are happy, they are known to paw their owners, or that on which they sit, with a kneading motion. Cats often use this action alongside purring to show contentment and affection for their owners. The action is often referred to as paddy-pawing, making muffins or treading paws. It is instinctive to cats, and they use it when they are young to stimulate the mother cat's nipple to release milk during nursing. Cats that are hand-raised by humans may lack this reflex.
Hunting and diet
Relative to size, domestic cats are very effective predators. They ambush and dispatch vertebrate prey using tactics similar to those of leopards and tigers by pouncing; they then deliver a lethal neck bite with their long canine teeth that severs the victim's spinal cord, or asphyxiate it by crushing the windpipe. They are one of the most graceful hunters on land with the blueprint to be lethal killers. From lions and leopards to cheetahs and jaguars, cats are very highly specialized with their own mode of attack.
The domestic cat can hunt and eat about one thousand species—many big cats will eat fewer than 100. 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. An exception is the leopard, which commonly hunts rabbits and many other smaller animals.
Cats have highly specialized teeth and a digestive tract suitable to the digestion 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 canines, it is highly developed in felines. The cat's tongue has sharp spines, or papillae, designed to retain and rip flesh from a carcass. These papillae are small backward-facing hooks that contain keratin and assist in their grooming. Unlike most carnivores, cats eat almost no vegetable matter apart from that found in the digestive tracts of their prey. Whereas bears and dogs commonly supplement their diet of meat with fruits, berries, roots, and honey when they can get them, cats feed exclusively on meat, usually freshly killed. Cats, including the great cats, have a genetic anomaly that prevents them from tasting sweetness [11], which is probably related to their meat-only habits.
In captivity, cats cannot be adapted to an unsupplemented vegetarian diet because they cannot synthesize all the amino acids they need from plant material. Specifically this applies to taurine, the absence of which causes the cat's retina to slowly degenerate, causing eye problems and (eventually) irreversible blindness. This condition is called central retinal degeneration (CRD). Cow's milk is a poor source of taurine and adult cats are generally lactose intolerant. Lactose-free milk is perfectly safe, but still not a substitute for meat. This contrasts with domesticated dogs, which commonly are fed a mixture of meat and vegetable products and have been adapted in some cases to a vegetarian diet. Despite this, however, the majority of brand-name cat foods are primarily grain based, often containing large amounts of corn or rice and supplemented with meats and essential vitamins. Some vegetarian owners feed their cats a vegetarian diet containing supplemental taurine.
Cats are also known to munch on grass, leaves, shrubs and houseplants. They do not eat a lot in one sitting, but prefer to have it as a snack. Eating vegetation in this way may aid the cat's digestive system and can prevent hairballs. [12].
Cats can be fussy eaters. This mostly happens when the vomeronasal, or Jacobson's, organ becomes sensitized to a specific food, at which point the cat will reject any food that doesn't fit the pattern it is expecting. Additionally, cats have been known to develop a fondness for "people food" such as barbecued chicken, bread, french fries, pepperoni pizza, ice cream, tomato soup, carrot juice, and carnitas burritos, as well as cat diet exotica such as corn kernels and diced cantaloupe. Many "people foods" are not good for cats; chocolate, for example, can be fatal due to the theobromine found in chocolate (see theobromine poisoning).
Domestic cats, especially young ones, are known for their love of string play. Many cannot resist a dangling piece of string, or a piece of rope drawn randomly and enticingly across the floor. This notorious love of string is often depicted in cartoons and photographs, which show kittens or cats playing with balls of yarn. This propensity is probably related to their hunting instinct. However, string is more often being replaced with a red dot laser pointer. This is because, if the string is ingested, it can be caught in the cat’s stomach or intestines causing illness or, in extreme cases, death. Some people discourage the use of laser pointers for play with pets, however, because of the risk of eye damage and the loss of satisfaction (especially for cats) associated with the successful capture of prey.
Because of their small size, domestic cats pose almost no danger to humans—the only hazard is the possibility of infection (or, rarely, rabies) from a cat bite or scratch.
Cats can be destructive to ecosystems in which they are not native and whose species did not have time to adapt to their introduction. In some cases, cats have contributed to or caused extinctions — for example, see the case of the Stephens Island Wren.
Hygiene
Cats are known for their cleanliness. They groom themselves by licking their fur. Their saliva is a powerful cleaning agent, but it can provoke allergic reactions in humans. Some people who are allergic to cats - typically manifested by hay fever, asthma or a skin rash - quickly acclimatise to a particular animal and live comfortably in the same house as it, while retaining an allergy to cats in general. Many cats also enjoy grooming humans or other cats. Some cats occasionally regurgitate hair balls of fur that have collected in their stomachs as a result of their grooming. Longhair cats are more prone to this than shorthairs. Hairballs can be prevented with certain cat foods and remedies that ease elimination of the hair. Cats expend nearly as much fluid grooming as they do urinating.
Indoor cats may be provided a litter box containing sand or similar commercial material (litter). This arrangement serves the same purpose as a toilet for humans. It should be cleaned daily and changed often (depending on the type of litter—clumping litter stays cleaner longer, but has been reported to cause health problems in some cats. [13]) A litterbox is recommended for indoor-outdoor cats as well. Litterboxes may pose a risk of toxoplasmosis transmission to susceptible pregnant women and immuno-compromised individuals. Transmission risk may be reduced by daily litterbox cleaning.
In addition, some cats may be toilet trained, eliminating the litterbox and its attending expense and odor. Training involves 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. When training is complete, the cat uses the toilet by perching over the bowl. [14]
Indoor cats will also benefit from being provided with a scratching post so they are less likely to ruin furniture with their claws.[15] Nails can be trimmed, but care should be taken to avoid cutting a vein in the quick of the claw.
Declawing
- Main article: onychectomy
Some cat owners choose to have their cat declawed (onychectomy). This major surgery removes the tip of each digit (from the first knuckle out) of the cat's forepaws. Some people are opposed to declawing, claiming it is inhumane. Declawing is not a simple procedure; serious complications can arise, such as an increased risk of infections, or life-long discomfort in the cat's paws. This operation is rare outside of North America. In Germany and Switzerland, declawing cats is explicitly forbidden by the laws against cruelty to animals.[16] In many other European countries, it is also forbidden under the terms of the European Convention for the Protection of Pet Animals, unless "a veterinarian considers [such] non-curative procedures necessary either for veterinary medical reasons or for the benefit of any particular animal". [17]
Where it is legal, some cat veterinarians refuse to do this type of surgery because it deprives the cat of its main defense ability, although cats usually learn to donkey kick or rake with their hind claws in defense. Other experts mention difficulties with the cat's typical stretching and exercise habits, which can lead to muscle atrophy. Declawing surgery requires anesthesia, which carries with it a small risk of death. Additionally, some experts believe that declawed cats are more inclined to bite. If a cat is not declawed at an early age, it becomes too dangerous to declaw them when they are older. However, many American cats are still declawed, often when the owner finds that it is the only option for keeping the cat (sometimes it is mandated by landlords). Some cats that are not declawed and cannot be retrained are either abandoned or turned in to animal shelters, where they may be euthanized. In Britain, where the prevailing style of ownership is indoor/outdoor, shelters find it difficult to rehome imported cats that had previously been declawed. One popular, relatively inexpensive alternative to declawing is the application of vinyl nail caps (marketed in the US as Soft Paws® or Soft Claws®) that are affixed to the claws with nontoxic glue, requiring periodic replacement when the cat sheds its claw sheaths (usually every four to six weeks).
Environment
The wild cat, 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. Wild cats are native to all continents other than Australasia and Antarctica. Their feces are usually dry, and cats prefer to bury them in sandy places. 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 breeds.
Cats enjoy heat and solar exposure, often sleeping in a warm area during the heat of the day. Cats like to be a lot warmer than humans do. People start to feel uncomfortable when their skin's temperature gets higher than about 44.5 °C (112 °F), but cats don't start to show signs of discomfort until their skin reaches about 52 °C (126 °F).
Being closely related to desert animals, cats can withstand the heat and cold of a temperate climate, but not for long periods. Although certain breeds such as the Norwegian Forest Cat and Maine Coon have developed more protection than others, they have little resistance against fog, rain and snowand struggle to maintain their 39 °C (102 °F) body temperature when wet. Most cats dislike immersion in water, but one exception is the Turkish Van cat. If a cat is continually exposed to water from a very young age, often it will develop a fondness for it; however, this rarely if ever occurs naturally.
Reproduction and genetics
Cats are seasonally polyestrous, which means they may have many heat periods 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 and recurs at regular intervals.
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. The female needs this stimulation for ovulation to begin. Because of this, 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.
The gestation period for cats is approximately 60 days. The size of a litter averages three to five kittens. Kittens are weaned at between six and seven weeks, and cats normally reach sexual maturity at six months (females) to seven months (males).
Completely white cats (not due to albinism, but white because of the dominant epistatic white (W) gene) with two blue eyes have a forty percent probability of being born deaf.
The deafness is an effect of the W gene. This gene produces a white coat because it completely masks any other color or pattern the cat has. Blue irises can result, and they are linked to deafness.