The Cat

Cat Anatomy

The domestic cat (Felis catus) is a small, usually furry, domesticated, carnivorous mammal. It is often called the housecat when kept as an indoor pet, or simply the cat when there is no need to distinguish it from other felines. Cats are valued by humans for companionship and their ability to hunt vermin and household pests.

General Information on the Cat

Domestic cats are similar in size to the other members of the genus Felis, typically weighing between 4 kilograms and 5 kilograms. However, some breeds, such as the Maine Coon, can occasionally exceed 11 kilograms. Conversely, very small cats (less than 1.8 kilograms) have been reported. The world record for the largest cat is 21.297 kilograms. The smallest adult cat ever officially recorded weighed around 1.36 kilograms. Cats average about 23–25 centimeters in height and 46 centimeters in head/body length (males being larger than females), with tails averaging 30 centimeters in length.

 

Fur

Humans produce only one type of hair, each strand from an individual follicle. In a cat, outer "guard," or primary hairs also grow individually from separate follicles; long and rigid, they keep the feline warm and dry. The more numerous secondary hairs of the undercoat, in contrast, grow in clusters from single follicles. This dense, insulating layer is close to the cat's skin and consists of both shorter, bristly "awn" hairs and soft, wavy "down" hairs. Depending on the cat's environment, the double-layered coat works like household insulation to prevent warmth from escaping when it's cold or entering when it's hot.

 

The earliest ancestors of domestic cats are said to have borne color-banded coats that helped them blend in with their surroundings. But as domestication lessened, the need for hunter's camouflage, mutations to solid colors such as red, black and white began to occur. And once cats with these mutated colors started crossbreeding, the color pattern palette burgeoned into countless variations.

Skeleton and Muscles

Unlike human arms, cat forelimbs are attached to the shoulder by free-floating clavicle bones, which allow them to pass their body through any space into which they can fit their heads.

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The cat skull is unusual among mammals in having very large eye sockets and a powerful and specialized jaw. Within the jaw, cats have teeth adapted for killing prey and tearing meat. When it overpowers its prey, a cat delivers a lethal neck bite with its two long canine teeth, inserting them between two of the prey's vertebrae and severing its spinal cord, causing irreversible paralysis and death.

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.

 

Like almost all members of the Felidae family, cats have protractable and retractable claws. In their normal, relaxed position the claws are sheathed with the skin and furaround the paw's 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. Most cats have five claws on their front paws, and four on their rear paws.

 

Behaviour (Social, Reproductive, Hunting)

Social

Although wildcats are solitary, the social behavior of domestic cats is much more variable and ranges from widely dispersed individuals to feral cat colonies that form around a food source, based on groups of co-operating females. Within such groups one cat is usually dominant over the others. Each cat in a colony holds a distinct territory, with sexually active males having the largest territories, which are about ten times larger than those of female cats and may overlap with several females' territories. Between these territories are neutral areas where cats watch and greet one another without territorial conflicts. Outside these neutral areas, territory holders usually 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 some cats cohabiting in colonies, cats do not have a social survival strategy, or a pack mentality and always hunt alone.

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Tail-raising indicates the cat's position in the group's social hierarchy, with dominant individuals raising their tails less often than subordinate animals. Nose-to-nose touching is also a common greeting and may be followed by social grooming, which is solicited by one of the cats raising and tilting its head.

However, some pet cats are poorly socialized. In particular, older cats may show aggressiveness towards newly arrived kittens, which may include biting and scratching; this type of behavior is known as Feline Asocial Aggression.

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Reproductive

Female cats are seasonally polyestrous, which means they may have many periods of heat over the course of a year, the season beginning in spring and ending in late autumn. Heat periods occur about every two weeks and last about 4 to 7 days. Multiple males will be attracted to a female in heat. The males will fight over her, and the victor wins the right to mate.

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Cats are superfecund; that is, a female may mate with more than one male when she is in heat, with the result that different kittens in a litter may have different fathers.

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The gestation period for cats is between 64–67 days, with an average length of 66 days. The size of a litter averages three to five kittens, with the first litter usually smaller than subsequent litters. Kittens are weaned at between six and seven weeks, and cats normally reach sexual maturity at 5–10 months (females) and to 5–7 months (males), although this can vary depending on breed. Females can have two to three litters per year, so may produce up to 150 kittens in their breeding span of around ten years.

 

Hunting

Cats feed on small prey, primarily birds and rodents. Feral cats and house cats that are free-fed tend to consume many small meals in a single day, although the frequency and size of meals varies between individuals. Cats use two hunting strategies, either stalking prey actively, or waiting in ambush until an animal comes close enough to be captured.

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Most breeds of cat have a noted fondness for settling in high places, or perching. In the wild, a higher place may serve as a concealed site from which to hunt; domestic cats may strike prey by pouncing from such a perch as a tree branch, as does a leopard. Other possible explanations include that height gives the cat a better observation point, allowing it to survey its territory. During a fall from a high place, 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.

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One poorly understood element of cat hunting behavior is the presentation of prey to human owners. Ethologist Paul Leyhausen proposed that 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 are placed at or near the top. Anthropologist and zoologist Desmond Morris, in his 1986 book Catwatching, suggests that when cats bring home mice or birds, they are attempting to teach their human to hunt, or trying to help their human as if feeding "an elderly cat, or an inept kitten".

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Since cats cannot fully close their lips around something to create suction, they use a lapping method with the tongue to draw liquid upwards into their mouths. Lapping at a rate of four times a second, the cat touches the smooth tip of its tongue to the surface of the water, and quickly retracts it, drawing water upwards.

Communication

• Purring – Purring is often a sign of contentment. Some cats purr when they are in extreme pain, or in labour, simply to try to calm themselves down. Purring therefore can be a sign of pleasure or pain; usually it is the former. Scientists have not yet been able to discover how purring works, but it is suspected that it is caused by minute vibrations in the voice box.

• Greeting – A particular sort of vocalization, such as a low meow or chirp or a bark, possibly with simultaneous purring.

• Distress – Mewing is a plea for help or attention often made by kittens. There are two basic types of this call, one more loud and frantic, the other more high-pitched. In older cats, it is more of a panicky repeated meow.

• Attention – Often simple meows and mews in both older cats and young kittens. A commanding meow is a command for attention, food, or to be let out.

• Protest – Whining meows.

• Frustration – A strong sigh or exhaled snort

• Happy – A meow that starts low then goes up and comes back down.

• Watching/interest – Cats will often "chatter" or "chirrup" on seeing something of interest. This is sometimes attributed to mimicking birdsong to attract prey or draw others' attention to it, but often birds are not present. 

A cat’s posture communicates its emotions. It's best to observe cats' natural behavior when they're by themselves, with humans, and with other animals. Their postures can be friendly or aggressive, depending upon the situation. Some of the most basic and familiar cat postures include the following:

• Relaxed posture – The cat is seen lying on the side or sitting. Its breathing is slow to normal, with legs bent, or hind legs laid out or extended when standing. The tail is loosely wrapped, extended, or held up. It also hangs down loosely when the cat is standing.

• Alert posture – The cat is lying on its belly, or it may be sitting. Its back is almost horizontal when standing and moving. Its breathing is normal, with its legs bent or extended (when standing). Its tail is curved back or straight upwards, and there may be twitching while the tail is positioned downwards.

• Tense posture – The cat is lying on its belly, with the back of its body lower than its upper body (slinking) when standing or moving back. Its legs, including the hind legs are bent, and its front legs are extended when standing. Its tail is close to the body, tensed or curled downwards; and there can be twitching when the cat is standing up.

• Anxious/Ovulating posture – The cat is lying on its belly. The back of the body is more visibly lower than the front part when the cat is standing or moving. Its breathing may be fast, and its legs are tucked under its body. The tail is close to the body and may be curled forward (or close to the body when standing), with the tip of the tail moving up and down (or side to side).

• Fearful posture – The cat is lying on its belly or crouching directly on top of its paws. Its entire body may be shaking and very near the ground when it’s standing up. Breathing is also fast, with its legs bent near the surface, and its tail curled and very close to its body when standing on all fours.

• Terrified posture – The cat is crouched directly on top of its paws, with visible shaking seen in some parts of the body. Its tail is close to the body, and it can be standing up, together with its hair at the back. The legs are very stiff or even bent to increase their size. Typically, cats avoid contact when they feel threatened, although they can resort to varying degrees of aggression when they feel cornered, or when escape is impossible.

Senses

Sight

Testing indicates that a cat's vision is greater at night in comparison to humans, but poorer in daylight. Cats, like dogs and many other animals, have a tapetum lucidum, which is a reflective layer behind the retina that sends light that passes through the retina back into the eye. 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.

Many 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. Cats can see some colours, and can tell the difference between red, blue and yellow lights, as well as between red and green lights. Cats are able to distinguish between blues and violets better than between colors near the red end of the spectrum.

 

Unlike humans, cats do not need to blink their eyes on a regular basis to keep their eyes lubricated (with tears). Unblinking eyes are probably an advantage when hunting. Cats will, however, "squint" their eyes, usually as a form of communication.

Cats have a wide variation in eye color, the most common colors being golden, green and orange. White cats having one blue and one other-colored eye are called "odd-eyed" and may be deaf on the same side as the blue eye. This is the result of the yellow iris pigmentation rising to the surface of only one eye, as blue eyes are normal at birth before the adult pigmentation has had a chance to express itself in the eye(s).

 

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, up to 64 kHz, which is 1.6 octaves above the range of a human, and even 1 octave above the range of a dog. 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.

 

Smell

A domestic cat's sense of smell is about fourteen times as strong as a human's. Cats have twice as many receptors in the olfactory epithelium as people do, meaning that cats have a more acute sense of smell than humans. 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, "sneering", "snake mouth", or "Flemming".

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Touch

A cat has about twenty-four movable vibrissae ("whiskers"), in four sets on each upper lip on either side of its nose (some cats may have more). There are also a few on each cheek, tufts over the eyes, bristles on the chin, the cat's inner "wrists", and at the back of the legs. The Sphynx (a nearly hairless breed) may have full length, short, or no whiskers at all.

Whiskers aid in hunting. High speed photography reveals that when a cat is unable to see its prey because it is too close to its mouth, its whiskers move so as to form a basket shape around its muzzle in order to precisely detect the prey's location. A cat whose whiskers have been damaged may bite the wrong part of its prey indicating that they provide cats with detailed information about the shape and activity of its prey. Whiskers may also help cats to detect scents more readily by directing air currents to their nose and mouth.

Whiskers are also an indication of the cat's attitude. Whiskers point forward when a cat is inquisitive and friendly, and lie flat on the face when the cat is being defensive or aggressive.