Cat

The cat ( Felis catus ), also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests. Cats have been associated with humans for at least 9,500 years, and are currently the most popular pet in the world. Owing to their close association with humans, cats are now found almost everywhere in the world.

Cats are similar in anatomy to the other felids, with strong, flexible bodies, quick reflexes, sharp retractable claws, and teeth adapted to killing small prey. As crepuscular predators, cats use their acute hearing and ability to see in near darkness to locate prey. Not only can cats hear sounds too faint for human ears, they can also hear sounds higher in frequency than humans can perceive. This is because the usual prey of cats (particularly rodents such as mice) make high frequency noises, so the hearing of the cat has evolved to pinpoint these faint high-pitched sounds. Cats also have a much better sense of smell than humans.

Despite being solitary hunters, cats are a social species and use a variety of vocalizations, pheromones and types of body language for communication. These include meowing, purring, trilling, hissing, growling, and grunting.

Cats have a rapid breeding rate. Under controlled breeding, they can be bred and shown as registered pedigree pets, a hobby known as cat fancy. Failure to control the breeding of pet cats by spaying and neutering and the abandonment of former household pets has resulted in large numbers of feral cats worldwide, with a population of up to 60 million of these animals in the United States alone.

As The New York Times wrote in 2007, "Until recently the cat was commonly believed to have been domesticated in ancient Egypt, where it was a cult animal", but a study that year revealed that the lines of descent of all house cats probably run through as few as five self-domesticating African Wildcats (Felis silvestris lybica) c. 8000 BC, in the Near East. The earliest direct evidence of cat domestication is a kitten that was buried alongside a human 9,500 years ago in Cyprus.

Nomenclature and etymology

The word cat derives from Old English catt , which belongs to a group of related words in European languages, including Welsh cath , Spanish gato , French chat ( ), Basque katu , Byzantine Greek κάτια kátia , Old Irish cat , Frisian and Dutch kat , German Katze , Lithuanian katė , Finnish Kissa , Armenian katu , and Old Church Slavonic kotka . The ultimate source of all these terms is Late Latin catus, cattus, catta "domestic cat", as opposed to feles 'European wildcat'. It is unclear whether the Greek or the Latin came first, but, like Arabic qiṭṭ and Nubian kàdíís , they were undoubtedly borrowed from a word in an Afro-Asiatic language akin to Berber kaddîska , meaning 'wildcat'. The term puss (as in pussycat) may come from Dutch poes or from Low German Puuskatte , dialectal Swedish kattepus , or Norwegian pus , pusekatt , all of which primarily denote a woman and, by extension, a female cat.

While wildcats are the ancestral species from which domestic cats are descended, there are several intermediate stages between domestic pet and pedigree cats and these entirely wild cats. The semi-feral cat is a cat that is not owned by any one individual, but is generally friendly to people and may be fed by several households. Feral cats are associated with human habitations and may be fed by people or forage in rubbish, but are wary of human interaction. Pseudo-wildcats are descended from domestic cats, but now tend to live entirely independently from people.

A group of cats is referred to as a "clowder", a male cat is called a "tom" (or a "gib", if neutered), and a female is called a "molly" or "queen". The male progenitor of a cat, especially a pedigreed cat, is its "sire", and its female progenitor is its "dam". An immature cat is called a "kitten" (which is also an alternative name for young rats, rabbits, hedgehogs, beavers, squirrels and skunks). In medieval Britain, the word kitten was interchangeable with the word catling .

A cat whose ancestry is formally registered is called a pedigreed cat, purebred cat, or a show cat. In strict terms, a pure-bred cat is one whose ancestry contains only individuals of the same breed. A pedigreed cat is one whose ancestry is recorded, but may have ancestors of different breeds. Cats of unrecorded mixed ancestry are referred to as domestic longhairs and domestic shorthairs or commonly as random-bred, moggies, mongrels, or mutt-cats.

Taxonomy and evolution

The Felids are a rapidly evolving family of mammals that share a common ancestor only 10–15 million years ago, and include, in addition to the domestic cat, lions, tigers, cougars, and many others. Within this family, domestic cats ( Felis catus ) are part of the genus Felis , which is a group of small cats containing seven species. Members of the genus are found worldwide and include the Jungle Cat ( Felis chaus ) of southeast Asia, the African Wildcat ( Felis silvestris lybica ), the Chinese Mountain Cat ( Felis bieti ) and the Arabian Sand Cat ( Felis margarita ).

All the cats in this genus share a common ancestor that probably lived around 6–7 million years ago in Asia. Although the exact relationships within the Felidae are still uncertain, both the Chinese Mountain Cat and the African Wildcat are close relations of the domestic cat and are both classed as subspecies of the Wildcat Felis silvestris . As domestic cats are little altered from wildcats, they can readily interbreed. This hybridization may pose a danger to the genetic distinctiveness of wildcat populations, particularly in Scotland and Hungary.

The domestic cat was first classified as Felis catus by Carolus Linnaeus in the tenth edition of his Systema Naturae of 1758. However, because of modern phylogenetics, domestic cats are now usually regarded as another subspecies of the Wildcat Felis silvestris . This has resulted in mixed usage of the terms, as the domestic cat can be called by its subspecies name, Felis silvestris catus . Wildcats have also been referred to as various subspecies of F. catus , but in 2003 the International Commission on Zoological Nomenclature fixed the name for wildcats as F. silvestris . The most common name in use for the domestic cat remains F. catus , following a convention for domesticated animals of using the earliest (the senior) synonym proposed. Sometimes the domestic cat is called Felis domesticus or Felis domestica , the term coined by German naturalist Johann Christian Polycarp Erxleben in 1777. These are not valid taxonomic names, and Linnaeus' binomial takes precedence.

Cats have either a mutualistic or commensal relationship with humans. However, in comparison to dogs, cats have not undergone major changes during the domestication process, as the form and behavior of the domestic cat are not radically different from those of wildcats, and domestic cats are perfectly capable of surviving in the wild. This limited evolution during domestication means that domestic cats tend to interbreed freely with feral cats, which distinguishes them from other domesticated animals. However, several natural behaviors and characteristics of wildcats may have preadapted them for domestication as pets. These traits include their small size, social nature, obvious body language, love of play and relatively high intelligence; they may also have an inborn tendency towards tameness.

There are two main theories about how cats were domesticated. In one, people deliberately tamed cats in a process of artificial selection, as they were useful predators of vermin. However, this has been criticized as implausible, because there may have been little reward for such an effort: cats generally do not carry out commands and, although they do eat rodents, other species such as ferrets or terriers may be better at controlling these pests. The alternative idea is that cats were simply tolerated by people and gradually diverged from their 'wild' relatives through natural selection, as they adapted to hunting the vermin found around humans in towns and villages.

Genetics

Main article: Cat geneticsBlue-eyed cats with white fur have a high incidence of genetic deafness.

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 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 ma