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 Funny Cat Videos Youtube

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The felids are a rapidly evolving family of mammals that share a common ancestor only 10–15 million years ago,[26] 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 approximately seven species (depending upon classification scheme).[1][27] 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.[28]

All the cats in this genus share a common ancestor that probably lived around 6–7 million years ago in Asia.[29] The exact relationships within the Felidae are close but still uncertain,[30][31] 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.[4][30] 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.[32]

The domestic cat was first classified as Felis catus by Carolus Linnaeus in the tenth edition of his Systema Naturae in 1758.[1][3] However, because of modern phylogenetics, domestic cats are now usually regarded as another subspecies of the wildcat, Felis silvestris.[1][4][33] This has resulted in mixed usage of the terms, as the domestic cat can be called by its subspecies name, Felis silvestris catus.[1][4][33] Wildcats have also been referred to as various subspecies of F. catus,[33] but in 2003 the International Commission on Zoological Nomenclature fixed the name for wildcats as F. silvestris.[34] 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.[34] Sometimes the domestic cat has been called Felis domesticus[35] or Felis domestica,[1] 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,[36] because Linnaeus's binomial takes precedence.[37]

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.[38][39] This limited evolution during domestication means that domestic cats tend to interbreed freely with wild relatives,[32] distinguishing them from other domesticated animals.[citation needed] Fully domesticated house cats also often interbreed with feral F. catus populations.[13] However, several natural behaviors and characteristics of wildcats may have pre-adapted them for domestication as pets.[39] These traits include their small size, social nature, obvious body language, love of play, and relatively high intelligence;[40]:12–17 they may also have an inborn tendency towards tameness.[39]

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.[41] 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.[4] 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.[4]

There is a population of Transcaucasus Black feral cats once classified as Felis daemon (Satunin, 1904), but now population is considered to be a part of domestic cat.
As cats are familiar and easily kept animals, their physiology has been particularly well studied; it generally resembles that of other carnivorous mammals but displays several unusual features probably attributable to cats' descent from desert-dwelling species.[35] For instance, cats are able to tolerate quite high temperatures: Humans generally start to feel uncomfortable when their skin temperature passes about 38 °C (100 °F), but cats show no discomfort until their skin reaches around 52 °C (126 °F),[54]:46 and can tolerate temperatures of up to 56 °C (133 °F) if they have access to water.[63]

Cats conserve heat by reducing the flow of blood to their skin and lose heat by evaporation through their mouth. They do not sweat, and pant for heat relief only at very high temperatures[64] (but may also pant when stressed). 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 both during the day and at night.[65]:1 Cats' feces are comparatively dry and their urine is highly concentrated, both of which are adaptations that allow cats to retain as much fluid as possible.[35] Their kidneys are so efficient that cats can survive on a diet consisting only of meat, with no additional water,[66] and can even rehydrate by drinking seawater.[65]:29[67]

Cats are obligate carnivores: their physiology has evolved to efficiently process meat, and they have difficulty digesting plant matter.[35] 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.[35] 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.[68] Another unusual feature is that the cat cannot produce taurine, with taurine deficiency causing macular degeneration, wherein the cat's retina slowly degenerates, causing irreversible blindness.[35] 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.[35]

A cat's gastrointestinal tract is 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.[69] These traits severely limit the cat's ability to digest and use plant-derived nutrients, as well as certain fatty acids.[69] 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,[70] and diets containing no animal products pose the risk of causing severe nutritional deficiencies.

Cats do eat grass occasionally. Proposed explanations include that grass is a source of folic acid or dietary fiber.

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