Your Pet Guide

In captivity, indoor cats typically live 14 to 20 years, although the oldest known cat, Creme Puff, lived to age 38. Some say that domesticated 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).

However, this is not always necessarily true, because a cat kept indoors is more inclined to have a shortened life due to obesity (sometimes leading to heart problems and diabetes) and lack of exercise. Having a cat be neutered, however, is almost universally regarded as a health benefit.

Some benefits of neutering are that castrated males cannot develop testicular cancer, spayed females cannot develop uterine or ovarian cancer, and both have a reduced risk of mammary cancer. The lifespan of feral cats is hard to determine accurately, although one study reported a median age of 4.7 years, with a range between 0 to 10 years.

Cats can suffer from a wide range of health problems, including infectious diseases, parasites, injuries and chronic disease. Vaccinations are available for many of these diseases, and domestic cats are regularly given treatments to eliminate parasites such as worms and fleas.

In addition to obvious dangers such as rodenticides, insecticides and weed killers, cats may be poisoned by many chemicals that are usually considered safe. This is because their livers are less effective at some forms of detoxification than those of other animals, including humans and dogs. Some of the most common causes of poisoning in cats are antifreeze and rodent baits.

It has also been suggested that cats may be particularly sensitive to environmental pollutants. When a cat has a sudden or prolonged serious illness without any obvious cause, it is therefore possible that it has been exposed to a toxin. Human medicines should never be given to cats. For example, the painkiller paracetamol (also called acetaminophen), sold under brand names such as Tylenol and Panadol is extremely toxic to cats: even very small doses can be fatal and need immediate treatment.

Even aspirin, which is sometimes used to treat arthritis in cats, is much more toxic to them than to humans and must be administered cautiously. Similarly, application of minoxidil (Rogaine) to the skin of cats, either accidentally or by well-meaning owners attempting to counter loss of fur, has sometimes been fatal.

Essential oils can be toxic to cats and there have been reported cases of serious illnesses caused by tea tree oil, and tea tree oil-based flea treatments and shampoos. Other common household substances that should be used with caution around cats include mothballs and other naphthalene products.

Phenol-based products are often used for cleaning and disinfecting near cats' feeding areas or litter boxes: such as Pine-Sol, Dettol (Lysol) or hexachlorophene, but these can sometimes be fatal. Ethylene glycol, often used as an automotive antifreeze, is particularly appealing to cats, and as little as a teaspoonful can be fatal.

Some human foods are toxic to cats; for example theobromine in chocolate can cause theobromine poisoning, although few cats will eat chocolate. Large amounts of onions or garlic are also poisonous to cats. Many houseplants are also dangerous, such as Philodendron species and the leaves of the Easter Lily, which can cause permanent and life-threatening kidney damage.

As a familiar and easily-kept animal, the physiology of cats has been particularly well studied and is generally similar to that of other carnivorous mammals. However, several features of cats' physiology are unusual and are probably due to their descent from desert-dwelling species.

For instance, cats are able to tolerate quite high temperatures, with humans starting to feel uncomfortable when their skin temperature passes about 44.5 °C (112 °F), in contrast cats show no discomfort until their skin reaches around 52 °C (126 °F). Unusually, a cat's body temperature does not vary throughout the day; this is part of cats' general lack of circadian rhythms and may reflect their tendency to be active in both day and night.

As well as being tolerant of high temperatures, cats' feces are usually dry and their urine is also highly concentrated, both of which are adaptations that allow cats to retain as much fluid as possible. Indeed, their kidneys are so efficient that cats can survive on a diet consisting only of meat, with no additional water, and can even rehydrate by drinking seawater.

Cats are obligate carnivores: their physiology has evolved to efficiently process meat, and they have difficulty digesting plant matter. In contrast to omnivores such as rats, which only require about 4% protein in their diet, about 20% of a cat's diet must be protein.

Cats are unusually dependent on a constant supply of the amino acid arginine, and a diet lacking arginine causes marked weight loss and can be rapidly fatal. Another unusual feature is that the cat also cannot produce the amino acid taurine, with taurine deficiency causing macular degeneration, where the cat's retina slowly degenerates, causing irreversible blindness.

Since cats tend to eat all of their prey, they obtain minerals by digesting animal bones and a diet composed only of meat may cause calcium deficiency. A cat's digestive tract is also adapted to meat eating, being much shorter than that of omnivores and having low levels of several of the digestive enzymes that are needed to digest carbohydrates.

These traits severely limits the cat's ability to digest and use plant-derived nutrients, as well as certain fatty acids. Despite the cat's meat-oriented physiology, several vegetarian or vegan cat foods have been marketed that are supplemented with chemically synthesized taurine and other nutrients, in attempts to produce a complete diet.

However, some of these products still fail to provide all the nutrients that cats require, and diets containing no animal products pose the risk of causing severe nutritional deficiencies.

The domesticated cat and its closest wild ancestor are both diploid organisms that possess 38 chromosomes and roughly 20,000 genes. About 250 heritable genetic disorders have been identified in cats, many similar to human inborn errors.

The high level of similarity among the metabolisms of mammals allows many of these feline diseases to be diagnosed using genetic tests that were originally developed for use in humans, as well as the use of cats in the study of the human diseases.

An interesting example of a mutation that is shared among all felines, including the big cats, is a mutant chemosensor in their taste buds that prevents them from tasting sweetness, which may explain their indifference to fruits, berries, and other sugary foods. In some breeds of cats congenital deafness is very common, with most white cats (but not albinos) being affected, particularly if they also have blue eyes.

The genes responsible for this defect are unknown, but the disease is studied in the hope that it may shed light on the causes of hereditary deafness in humans. Since a large variety of different coat patterns exist within the various cat breeds, the cat is an excellent animal to study the coat genetics of hair growth and coloration.

Several genes interact to produce cats' hair color and coat patterns. Different combinations of these genes give different phenotypes. For example, the enzyme tyrosinase is needed to produce the dark pigment melanin and Burmese cats have a mutant form that is only active at low temperatures, resulting in color appearing only on the cooler ears, tail and paws.

A completely inactive gene for tyrosinase is found in albino cats, which therefore lack all pigment. Hair length is determined by the gene for fibroblast growth factor 5, with inactive copies of this gene causing long hair.

The Cat Genome Project, sponsored by the Laboratory of Genomic Diversity at the U.S. National Cancer Institute Frederick Cancer Research and Development Center in Frederick, Maryland, aims to help the development of the cat as an animal model for human hereditary and infectious diseases, as well as contributing to the understanding of the evolution of mammals.

This effort led to the publication in 2007 of an initial draft of the genome of a Abyssinian cat called Cinnamon. The existence of a draft genome has led to the discovery of several cat disease genes, and even allowed the development of cat genetic fingerprinting for use in forensics.

Cats have excellent night vision and can function at only one-sixth the light level required for human vision. This is partly the result of cat eyes having a tapetum lucidum, which reflects any light that passes through the retina back into the eye, thereby increasing the eye's sensitivity to dim light.

Another adaptation to dim light is the large pupils of cats' eyes. Unlike some big cats, such as tigers, domestic cats have slit pupils.

These slit pupils can focus bright light without chromatic aberration, and are needed since the domestic cat's pupils are much larger, relative to their eyes, than the pupils of the big cats.

Indeed, at low light levels a cat's pupils will expand to cover most of the exposed surface of its eyes. However, domestic cats have rather poor color vision and can only see two colors: blue and green, and are less able to distinguish between red and green, although they can achieve this in some conditions.

Cats have excellent hearing and can detect an extremely broad range of frequencies. They can hear higher-pitched sounds than either dogs or humans, detecting frequencies from 55 Hz up to 79 kHz, a range of about 7 octaves; while humans can only hear from 31 Hz up to 18 kHz, and dogs hear from 67 Hz to 44 kHz, which are both ranges of about 6 octaves.

Cats do not use this ability to hear ultrasound for communication but it is probably important in hunting, since many species of rodents make ultrasonic calls. Cats' hearing is also extremely sensitive and is among the best of any mammal,being most sensitive in the range of 500 Hz to 32 kHz.

This sensitivity is further enhanced by the cat's large movable outer ears (their pinnae), which both amplify sounds and help a cat sense the direction from which a noise is coming. Cats have an acute sense of smell, which is due in part to their well-developed olfactory bulb and also to a large surface of olfactory mucosa, in cats this mucosa is about 5.8 cm2 in area, which is about twice that of humans and only 1.7-fold less than the average dog.

Cats respond strongly to the smell of nepetalactone, a compound found in catnip, and can detect this substance at less than one part per billion. Cats are also sensitive to pheromones such as 3-Mercapto-3-methylbutan-1-ol, which they use to communicate through urine spraying and marking with scent glands.

Due to a mutation in an early cat ancestor, one of two genes necessary to taste sweetness may have been lost by the cat family. Their taste buds instead respond to amino acids, bitter tastes and acids. To aid with navigation and sensation, cats have dozens of movable vibrissae (whiskers) over their body, especially their face.

These provide information on the location of objects in the dark, both by touching objects directly and by sensing air currents; they also trigger protective blink reflexes to protect the eyes from damage.