The reindeer (Rangifer tarandus), also known as caribou in North America, is a species of deer native to Arctic, Subarctic, tundra, boreal and mountainous regions. This includes both sedentary and migratory populations. While overall widespread and numerous, some of its subspecies are rare and at least one has already gone extinct. Reindeer vary considerably in colour and size. In most populations, both sexes grow antlers annually, but females lack antlers in a few. Antlers are typically larger in males. Hunting of wild reindeer and herding of semi-domesticated reindeer (for meat, hides, antlers, milk and transportation) are important to several Arctic and Subarctic peoples. The reindeer is well known in folklore due to Santa Claus's sleigh being pulled by flying reindeer, a popular element of Christmas. In Lapland, reindeer pull pulks.

source: wikipedia