reindeer, ruminant mammal, genus Rangifer, of the deer family, found in arctic and subarctic regions of Eurasia and North America. It is the only deer in which both sexes have antlers. The Eurasian reindeer, Rangifer tarandus, is a small deer, the male standing about 4 ft (120 cm) high at the shoulder and weighing about 250 lb (113 kg), but it is extremely strong and has great powers of endurance. A reindeer can travel 40 mi (64 km) a day, pulling twice its own weight on a sled. Reindeer have long fur, light brown in summer and whitish in winter, with dense woolly undercoats. The antlers are many pronged, with characteristically curved main stems that sweep back and up from the forehead, then turn forward. The hooves are broad and rounded and in winter become concave, providing a good grip on icy ground. Reindeer are gregarious and migratory; they travel hundreds of miles between their summer and winter grounds in herds of up to 200,000 animals. They feed on a variety of plant matter, particularly grasses in summer and lichen in winter.
Reindeer have been hunted for perhaps 30,000 years. They have been domesticated for many centuries in Lapland, N Siberia, and Mongolia, where they may be used for meat, milk, clothing, and transportation. They are used both to pull sleds and to carry burdens and riders. The Laplanders until recently were completely dependent upon the reindeer for their livelihood and followed the herds on their annual migrations.
Reindeer living in a wild state in Eurasia are probably descended in part from domesticated strains. The wild reindeer of North America, called caribou, are larger than, but otherwise quite similar to, the Eurasian species. They have never been domesticated. Domesticated reindeer were introduced into Alaska from Siberia in the 1890s and became essential to the economy of the Alaskan Eskimo. Herds were established in Canada in the 1930s.
Reindeer are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Artiodactyla, family Cervidae.
See P. S. Zhigunov, ed., Reindeer Husbandry (tr. 1968); D. F. Olson, Alaska Reindeer Herdsmen (1969).