Reindeer, known as caribou in North America, are deer in the genus Rangifer. Traditionally, reindeer were thought to be one species, Rangifer tarandus, with about ten subspecies. A 2022 revision of the genus elevated five of the subspecies to species (see Taxonomy). They have a circumpolar distribution and are native to the Arctic, sub-Arctic, tundra, boreal forest, and mountainous regions of northern Europe, Siberia, and North America. Reindeer occur in both migratory and sedentary populations, and their herd sizes vary greatly in different geographic regions. Reindeer are unique among deer (Cervidae) in that females may have antlers, although the prevalence of antlered females varies by subspecies. The tundra subspecies are adapted for extreme cold, and some are adapted for long-distance migration. (Source: Wikipedia.org, CC BY-SA)