Although reindeer are quite numerous, some species and subspecies are in decline and considered vulnerable. ( t.) platyrhynchus), to the largest, Osborn's caribou ( R. Reindeer vary greatly in size and color from the smallest, the Svalbard reindeer ( R. The tundra subspecies are adapted for extreme cold, and some are adapted for long-distance migration. Reindeer occur in both migratory and sedentary populations, and their herd sizes vary greatly in different regions.
More recent studies suggest the splitting of reindeer and caribou into six distinct species over their range.
It is the only representative of the genus Rangifer. The reindeer or caribou ( Rangifer tarandus) is a species of deer with circumpolar distribution, native to Arctic, subarctic, tundra, boreal, and mountainous regions of Northern Europe, Siberia, and North America. Reindeer range: North American (green), Eurasian (red), and Alaskan introduced (orange) See text, traditionally 1, but possibly up to 6