Saturday, April 21, 2012
Lesson 1: Cat anatomy
Cats have seven cervical vertebrae like almost all mammals, thirteen thoracic vertebrae (humans have twelve), seven lumbar vertebrae (humans have five), three sacral vertebrae (humans have five
because of their bipedal posture), and, except for Manx cats, 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 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 heads.
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 lives 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 behavior also extends into adulthood, when a male will grab the female by the scruff to immobilize her while he mounts, and to prevent her from running away as the mating process takes place.
This technique 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 its 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.
The cats are highly territorial and secreting odors plays a major role in cat communication. The nose helps cats to identify territories, other cats and mates, to locate food, and for various other causes.
A cat's sense of smell is believed to be about fourteen times stronger than that of humans. The bit of nose we see, the nose leather is quite tough to allow it to absorb rather rough treatment sometimes.
The color varies according to the genotype (genetic makeup) of the cat. Cat's skin has the same color as the fur but the color of the nose leather is probably dictated by a dedicated gene.
Cats with white fur have skin susceptible to damage by ultraviolet light that may cause cancer. Extra care is required when she/he goes outside in hot sun.
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 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 cats' ears is an important clue to their mood.
Like nearly all members of the family Felidae, 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 voluntarily extend their claws on one or more paws.
They may extend their claws in hunting or self-defense, climbing, "kneading", or for extra traction on soft surfaces (bedspreads, thick rugs, skin, 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 can become entangled in carpet or thick fabric, which can 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 and feral cats are prone to polydactylyism, (particularly in the east coast of Canada and northeast coast of the United States) and can have six or seven toes.
The fifth front claw (the dewclaw) is proximal to the other claws. 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.
Cats have highly specialized teeth for the killing of prey and the tearing of meat. The premolar and first molar, together the carnassial pair are located on each side of the mouth.
These teeth efficiently function 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 groom. The cat's oral structures provide for a variety of vocalizations used for communication, including meowing, purring, hissing, growling, squeaking, chirping, clicking, and grunting.
Cats also employ a variety of body language: position of ears and tail, relaxation of whole body, kneading of paws, all are indicators of mood.
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 usually is between 150 and 180 bpm, about twice that of a human (average 80 bpm).
Cats, like dogs, are digitigrades. They walk directly on their toes, with 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. The two back legs make the cat able to leap far distances and fall from high places without getting hurt.
source : http://en.wikipedia.org/wiki/Cat_anatomy
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