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 about seven species (depending upon classification scheme). Members of the genus are found worldwide and include the jungle cat (Felis chaus) of southeast Asia, European wildcat (F. silvestris silvestris), African wildcat (F. s. lybica), the Chinese mountain cat (F. bieti), and the Arabian sand cat (F. margarita), among others.

All the cats in this genus share a common ancestor that probably lived around 6–7 million years ago in Asia. The exact relationships within the Felidae are close but still uncertain, e.g. the Chinese mountain cat is sometimes classified (under the name Felis silvestris bieti) as a subspecies of the wildcat, like the North African variety F. s. lybica. As domestic cats are little altered from wildcats, they can readily interbreed. This hybridization poses a danger to the genetic distinctiveness of wildcat populations, particularly in Scotland and Hungary, and possibly also the Iberian Peninsula.

The domestic cat was first classified as Felis catus by Carolus Linnaeus in the 10th edition of his Systema Naturae in 1758. However, because of modern phylogenetics, domestic cats are now usually regarded as another subspecies of the wildcat, F. 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 has been called Felis domesticus or Felis domestica, as proposed by German naturalist J. C. P. Erxleben in 1777, but these are not valid taxonomic names and have been used only rarely in scientific literature, because Linnaeus's 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 wild relatives, distinguishing them from other domesticated animals.[citation needed] Fully domesticated house cats also often interbreed with feral F. catus populations. 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;:12–17 they may also have an inborn tendency towards tameness.

Two main theories are given 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 the reward for such an effort may have been too little; 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.

A population of Transcaucasian black feral cats was once classified as Felis daemon (Satunin, 1904), but now this population is considered to be a part of domestic cat.