Les félins ou félidés (Felidae) constituent une famille de carnivores féliformes. On y distingue les grands félins (Pantherinae) des petits félins (Felinae). Parmi leurs traits caractéristiques figurent leur tête ronde au crâne raccourci, leur mâchoire dotée d’environ trente dents, et leurs griffes rétractiles, exception faite du guépard, du chat viverrin et du chat à tête plate. Les félins sont digitigrades, c’est-à-dire qu’ils marchent en appuyant sur leurs doigts (la plante du pied ne se pose pas sur le sol).
Proailurus, qui vivait il y a environ 25 millions d’années dans la période de l’Oligocène, est à l'heure actuelle considéré comme le plus vieux félidés connu. On considère Pseudaelurus comme le dernier ancêtre commun des félins modernes.
The tiger (Panthera tigris) is the largest cat species, reaching a total body length of up to 3.3 m (11 ft) and weighing up to 306 kg (675 lb). Its most recognizable feature is a pattern of dark vertical stripes on reddish-orange fur with a lighter underside. It has exceptionally stout teeth, and the canines are the longest among living felids with a crown height of as much as 74.5 mm (2.93 in) or even 90 mm (3.5 in). In zoos, tigers have lived for 20 to 26 years, which also seems to be their longevity in the wild. They are territorial and generally solitary but social animals, often requiring large contiguous areas of habitat that support their prey requirements. This, coupled with the fact that they are indigenous to some of the more densely populated places on Earth, has caused significant conflicts with humans.
Tigers once ranged widely across Asia, from Turkey in the west to the eastern coast of Russia. Over the past 100 years, they have lost 93% of their historic range, and have been extirpated from southwest and central Asia, from the islands of Java and Bali, and from large areas of Southeast and Eastern Asia. Today, they range from the Siberian taiga to open grasslands and tropical mangrove swamps. The remaining six tiger subspecies have been classified as endangered by IUCN. The global population in the wild is estimated to number between 3,062 and 3,948 individuals, down from around 100,000 at the start of the 20th century, with most remaining populations occurring in small pockets isolated from each other. Major reasons for population decline include habitat destruction, habitat fragmentation and poaching. The extent of area occupied by tigers is estimated at less than 1,184,911 km2 (457,497 sq mi), a 41% decline from the area estimated in the mid-1990s.