Pet Cats

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 believed to be the African wild cat, Felis silvestris lybica. The cat has been living in close association with humans for at least 3,500 years[1].

There are dozens of breeds of cats, some hairless or tailless, and they exist in a variety of different colors. They are skilled predators and have been known to hunt over one thousand different species for food. They are also intelligent animals, and some can either be trained or learn by themselves to manipulate simple mechanisms such as lever-handled doors and flush toilets.

They communicate by calling ("meow"/"miaou"), purring, hissing, growling, and body language. Cats in colonies use a mix of vocalizations and body language to communicate with each other.

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 those of the ancient Egyptians, ancient Chinese, and Norse.

Nomenclature
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. An immature cat is called a kitten (which is also an alternate name for young rats, rabbits, hedgehogs, beavers, and squirrels). In medieval Britain, the word kitten was interchangeable with the word catling. A cat whose ancestry is formally registered is called a pedigree cat, purebred 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. 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. However, generally speaking, purebreds are less than ten percent of the total feline population (ASPCA Complete Guide to Cats by James R. Richards, DVM).

Characteristics

Physical features
 
A cat grooming itselfCats 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. This is very unhealthy for the cat, and should be prevented through diet and exercise (playing), especially for cats living exclusively indoors.

In captivity, indoor cats typically live 14 to 20 years, though the oldest-known cat lived to age 36.[2] 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 litter benefit from reduced risk of mammary cancer.[3] 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.

Ears
Thirty-two individual muscles in the ear allow for a manner of directional hearing; [4] 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 its ears back, to accompany the growling or hissing sounds it makes.

Metabolism
 
An orange tabby taking a "cat nap"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 (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 nocturnal nature, cats are often known to enter a period of increased hyperactivity and playfulness during the evening, dubbed the 'evening crazies' or 'night crazies' by some.

The temperament of a cat 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). 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.

Legs

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. This is known as the cat 'righting reflex'. 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. 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, minimising noise and visible tracks. This also provides sure footing for their hind paws when they navigate rough terrain.

Like many predators, cats have retractable claws. This is actually a misnomer because in their normal, relaxed position the claws are sheathed with the skin and fur around the toe pads. This is done to keep the claws sharp by preventing wear from contact with the ground. It is only by stretching, such as swatting at prey, that the connecting tendons are pulled taut, forcing the claws to extend. Thus, extending the claws is an involuntary action.

Senses
 
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.

While a cat's senses of smell and hearing may not be as keen as, say, those of a mouse, they are superior in many ways to those of humans. These along with the cat's highly advanced eyesight, taste, and touch receptors make the cat extremely sensitive among mammals.

Sight
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 seven 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.

Hearing
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.

Smell
A domestic cat's sense of smell is about fourteen 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, horses and big cats.

Touch
 
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 back of a cat's "wrists", and there are similar hairs comprising the cat's eyebrows. 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.

Taste
According to National Geographic December 8, 2005 cats cannot 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 is the cause or the result of it.

Communication

Meow
 
A cat vocalizingThe unique sound a cat makes is rendered onomatopoeically as "meow" or similar variants ("miaow", "miau" etc.) in most European languages. Japanese has it as "nyaa" or "nyan", Korean as "yaong" or "nyaong". In Arabic the sound is transcribed as "mowa'a". Other variants exist throughout the world. 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 often, so their call may remain similar to that of a kitten through adulthood.

Purr

Cats can also produce a purring noise that typically indicates that the cat is happy, but also can mean that it feels distress. 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 or dying.

Other Noises

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. Like any injury, Cat scratches can become infected, and in extreme cases can result in cat scratch fever.

Cats are also known to make chirping or chattering 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). Recent animal behaviorists have come to believe this noise is a "rehearsal behavior" in which it anticipates or practices the killing of prey, because the sound usually accompanies a jaw movement similar to the one they use to kill their prey (the "killing bite" which saws through the victim's neck vertebrae).

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 [11]. 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.