Caribou, mammal, North American deer of the same species as the reindeer of Eurasia. Caribou range in height from 87 to 140 cm (34 to 55 in) at the shoulder and weigh from 60 to 318 kg (130 to 701 lb). Both males and females have antlers, but the female's are smaller and simpler. Two principal groups exist: the Barren Ground, or Arctic, caribou and the woodland caribou.

Barren Ground caribou are native to the tundra regions of northern Canada, Greenland, and Alaska. Historically, the Inuit people living in Arctic regions have depended on these animals for survival, using every part of the body for food, implements, or clothing. The caribou usually live in small herds of cows and calves and a few bulls. Most of the older bulls stay in separate small bands, except during the rut (mating season), and travel on the fringes of migrating herds. Breeding takes place in September and October, and the calves are born in May and June. These caribou have a grey or light brown summer coat and a white winter coat. In winter they gather in large herds and migrate south to warmer Canadian forests, sometimes travelling 5,000 km (more than 1,900 mi), then return north in spring. The staple diet of caribou is lichens, but they also eat grasses, shrubs, tree shoots, and fungi. Plans for oil- and gas-pipeline construction in Alaska and Canada were altered, through environmentalist efforts, so as not to interfere with caribou migration.

Of less economic significance are the woodland caribou, which are darker and stockier and have heavier antlers than Barren Ground caribou. At one time they were common from Maine to Montana, but they have since been exterminated in most parts of the United States.

Scientific classification: The caribou belongs to the family Cervidae. It is classified as Rangifer tarandus.