Carnivora is a diverse order of placental mammals that includes 260 mostly carnivorous (meat-eating) species, including the familiar domestic cat and dog. Carnivora consist of three superfamilies: Canoidea (dogs, badgers, skunks, weasels, ferrets, martens, minks, otters, polecats, raccoons, bears, and the extinct bear-dogs), Feloidea (cats and other felids, mongooses, hyenas, civets, and the extinct paleofelids), and Pinnipedia (walruses, seals, and sea lions).
Species in order Carnivora tend to be terrestrial carnivores with sharp, deeply-rooted teeth, including incisors, often adapted for killing smaller animals and tearing off their flesh. Carnivorans also share a similar skull structure, with strong jaw muscles for biting. Some members of Carnivora, like bears, are omnivores, eating cereals, roots, and other plants along with a meat-based diet. Others, like badgers, are insectivores, primarily eating earthworms, insects, and grubs. Still others, like the hyena, are scavengers, consuming the remains of animals killed by carnivores or recently dead of natural causes. Felids have the largest incisors of carnivorans, the epitome being reached in the extinct saber-tooth tiger.
Carnivorans range in size from the smallest domestic cats, such as the record-setting Mr. Peebles from Illinois, who weighed only 3 lb (1.2 kg) and is 6 in (15 cm) long, to a record-setting elephant seal that weighs 11,000 lb (5000 kg) and measures 22.5 ft (6.9 m) in length. Mr. Peebles' case is actually due to a genetic defect, however, and the Least Weasel, with a lower weight and longer body, is sometimes considered the smallest member of Carnivora. Another of the large carnivorans is the polar bear, which is also the largest purely terrestrial carnivore, weighing up to 1,300 lb (600 kg), and measuring 10 ft (3 m) in length.
Order Carnivora consists of all the animals that resulted from the radiation of early placental mammalian carnivores. This occurred about 42 million years ago, when felids and canids diverged from primitive mammalian carnivores called miacids, which resembled present-day martens. Miacids are considered carnivoramorphs rather than true members of order Carnivora. Since the time of the miacids, carnivorans have adapted to fill a wide range of habitats, and are sometimes considered to be the smartest mammalian order apart from primates.