Carnivora (/kɑrˈnɪvɵrə/ or /ˌkɑrnɨˈvɔərə/; from Latin carō (stem carn-) "flesh", + vorāre "to devour") is a diverse order that includes over 280 species of placental mammals. Its members are formally referred to as carnivorans, whereas the word "carnivore" (often popularly applied to members of this group) can refer to any meat-eating organism. Carnivorans are the most diverse in size of any mammalian order, ranging from the least weasel (Mustela nivalis), at as little as 25 g (0.88 oz) and 11 cm (4.3 in), to the giant short-faced bear (Arctodus simus), which can weigh up to 957 kg (2,110 lb), to the polar bear (Ursus maritimus), which can weigh up to 1,000 kg (2,200 lb), to the southern elephant seal (Mirounga leonina), whose adult males weigh up to 5,000 kg (11,000 lb) and measure up to 6.9 m (23 ft) in length.
The first carnivoran was a carnivore, and nearly all carnivorans today primarily eat meat. Some, such as most felids and pinnipeds, depend entirely on meat for their nutrition. Others, such as raccoons and bears, depending on the local habitat, are more omnivorous: the giant panda is almost exclusively a herbivore, but will take fish, eggs and insects, while the polar bear subsists mainly on seals. Carnivorans have teeth, claws adapted for catching and eating other animals. Many hunt in packs and are social animals, giving them an advantage over larger prey.
Carnivorans apparently evolved in North America out of members of the family Miacidae (miacids) about 42 million BC. They soon split into catlike and doglike forms (Feliformia and Caniformia). Their molecular phylogeny shows the extant Carnivora are a monophyletic group, the crown group of the Carnivoramorpha.