The informal term "big cat" is typically used to refer to any of the four largest (living) members of the entire Panthera genus. Among the five total species within the Panthera genus, these four are the only cats that are able to roar. In descending order of their maximum potential size, these four species are: tigers, lions, jaguars, and leopards, with the tiger (Panthera tigris) being the largest. A more liberal and expansive definition is sometimes used which may include the snow leopard, puma, clouded leopard, Sunda clouded leopard and/or cheetah, although these added species do not roar.
Despite enormous differences in size, various species of cat are quite similar in both structure and behaviour, with the exception of the cheetah, which significantly stands out from the other big and small cats. All cats are carnivores and efficient apex predators. Their range includes the Americas, Africa, Asia, and Europe.