Cats

The cat (or domestic cat, house cat) is a small domesticated carnivorous mammal. It is valued by humans for its companionship and its ability to destroy vermin. A skilled predator, the cat is known to hunt over 1,000 species for food. Intelligent, the cat can be trained to obey simple commands, and has been known to teach itself to manipulate simple mechanisms (see cat intelligence).

The trinomial name of the domestic cat is Felis silvestris catus. Its closest pre-domesticated ancestor is believed to be the African wild cat, Felis silvestris lybica.[1] Humans have developed several dozen breeds of cat, in a variety of colours.

Cats have lived in close association with humans for at least 9,500 years,[2]. Legends and myths about the cat exist in many cultures, from the ancient Egyptians and Chinese to the Vikings. They have been both revered and vilified by different cultures.

Cats use more than one hundred vocalizations and types of body language for communication, including mewing ("meow" or "miaou"), purring, hissing, growling, chirping, clicking, and grunting.[3] Cats have even been observed mimicking the calls of birds.

Like horses and other domesticated animals, cats can sometimes become feral, living effectively in the wild. Feral cats will often form small feral cat colonies. Animal welfare organizations note that few abandoned cats are able to survive long enough to become feral, most being killed by vehicles, or succumbing to starvation, predators, exposure, or disease.

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 lbs) [8] have been reported.

General anatomy of a cat.

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General anatomy of a cat.

In captivity, indoor cats typically live 14 to 20 years, though the oldest-known cat lived to age 36.[9] Domestic 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 spayed or neutered. Some such benefits are: neutered male cats cannot develop testicular cancer, spayed female cats cannot develop ovarian cancer, and both have a reduced risk of mammary cancer. [10]

Cats also possess rather loose skin; this enables 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 [11]. 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.[12][13].

The particular 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 have a tendency to relax and 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 quite a bit 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 also at the chest and front paws. Often (much like a small child) a cat will lie with it's head and front paws over a person's shoulder, and its back legs and rump supported under the person's arm.

Like almost all mammals, cats possess seven cervical vertebrae. They have thirteen thoracic vertebrae (compared to twelve in humans), seven lumbar vertebrae (compared to five in humans), three sacral vertebrae like most mammals (humans have five because of their bipedal posture), and twenty-two or twenty-three caudal vertebrae (humans have three to five, fused into an internal coccyx). The extra lumbar and thoracic vertebrae account for the cat's enhanced spinal mobility and flexibility, compared to humans; the caudal vertebrae form the tail, used by the cat for counterbalance to the body during quick movements. [14].

Ears

Sixty-two individual muscles in the ear allow for a manner of directional hearing:[15] 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. Cats will also turn their ears back when they are playing, or occasionally to show interest in a sound coming from behind them.

Metabolism

Cats commonly sleep curled into a tight ball.

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Cats commonly sleep curled into a tight ball.

Cats conserve energy by sleeping more than most animals, especially as they grow older. Daily durations of sleep vary, 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 hyperactivity and playfulness during the evening and early morning, dubbed the "evening crazies", "night crazies" or "mad half-hour" by some.[16][17]

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 oC (101 and 102.2 oF).[18] A cat is considered febrile (hyperthermic) if it has a temperature of 39.5 oC (103 oF) or greater, or hypothermic if less than 37.5 oC (100 oF). For comparison, humans have a normal temperature of approximately 36.8 oC (98.2 oF). 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.