All cats have the same complement of pre-installed parts and capabilities. If yours is missing one or more of the parts or systems herein described, contact an authorized service provider immediately.

The Head

Eyes: Each model contains two. Feline irises form a distinctive vertical slit, rather than the circle common in most mammals. The visual system is protected by a “third eyelid” that deploys from the interior corner of each eye socket.

Ears: Each model contains two. A cat’s outer ear can rotate 180 degrees, allowing it to scan its environment for particular sounds and pinpoint them with great precision.

Nose: The cat’s sense of smell is superior to that of humans but markedly inferior to that of dogs. A newborn kitten’s nose is already so finely tuned that it can differentiate one of its mother’s nipples from the others via smell.

Tongue: The hundreds of tiny barbs covering its surface are used for several tasks—including scraping meat from the bones of prey; washing and grooming the coat; drying wet fur, and acting as a temperature control system (by relieving overheating through panting and the evaporation of saliva). Cats drink by forming a depression in the front of their tongues and using it to convey liquid to their mouths.

Teeth: Felines do not chew their food; they chop it. Adult domestic cats come equipped with 30 teeth, all of which are designed for shredding meat. They use their large fangs, or “canines,” to break the necks of their prey. In the case of domestic felines, these teeth are optimally spaced for dispatching mice.

Whiskers: Positioned in sets of 12 on each side of the muzzle, these thick, deeply set hairs are highly developed sensory organs. Among other things, they can gauge changes in wind direction and detect nearby movement in extreme low-light environments. They also help the cat determine if it can squeeze through a tight space (the whiskers are usually the same span as the feline’s body at its widest point, unless the cat is obese or extremely pregnant). During hunting, the cat can push the whiskers forward, to provide information about the prey it is grappling with. 

CAUTION: It is unwise to cut a cat’s whiskers. Doing so will prevent the cat from doing the things described above (as well as several other subroutines that are necessary for the day-to-day comfort and survival of the feline). Furthermore, the whiskers are extremely sensitive; cutting them is certain to make the cat experience pain.

The Body

Coat: Most cat coats incorporate three hair types: a topcoat composed of “guard hairs,” and an undercoat of bristly “awn hairs” and softer “down hairs.” Purebred varieties may lack one or more of these. For instance, the Persian has no or very few awn hairs, and the nearly coatless Sphynx carries only a small number of down hairs.

Output Port: Products from the cat’s waste discharge system are extremely rich in nitrogen—so rich that they can “burn” vegetation just as an over-application of fertilizer can.

Genitals: Females reach sexual maturity at 7 to 12 months; males at 10 to 14 months. The head of the male cat’s penis is covered with spines, which stimulate ovulation in the female during intercourse.

Paws: Cats walk on the tips of their “fingers.” This design feature allows them to sprint as fast as 31 mph (50 km/h). Cats can have a “dominant” forepaw, just as humans have dominant hands. About 40 percent are left-pawed, 20 percent right-pawed, and 40 percent ambidextrous.

Claws: Each paw is equipped with a set of claws optimized for climbing, fighting, and grasping prey. They can be retracted when not in use. This design option is exclusive to felines.

Tail: Used as a mood-signaling device and as a balancing aid while climbing, the tail may contain anywhere from 14 to 28 vertebrae.

Nipples: Males and females are equipped with a set of these docking ports. They are nonfunctional in males.

Weight: An adult domestic cat usually weighs between 6 and 12 pounds (3–5.5 kg). Height: Unlike domestic dogs, cats are fairly uniform in size. An average domestic cat stands about 12 inches (30 cm) tall at the shoulder.