Reindeer
The Reindeer is a deer from the Arctic and Subarctic. The Reindeer varies considerably in colour and size, and both genders grow antlers, though these are larger in the males and there are a few populations where females lack them completely.
The Reindeer is a widespread and numerous species in the northern Holarctic, being present in both tundra and taiga. Originally, the Reindeer was found in Scandinavia, eastern Europe, Russia, Mongolia, and northern China. In North America, it was found in Canada, Alaska (USA), and the northern conterminous USA from Washington to Maine.
Mating occurs from late September to early November. Males battle for access to females. Two males will lock each other's antlers together and try to push each other away. The most dominant males can collect as many as 15-20 females to mate with. A male will stop eating during this time and lose much of its body reserves. Calves may be born the following May or June. After 45 days, the calves are able to graze and forage but continue suckling until the following autumn and become independent from their mothers.
Source: en.wikipedia.org/wiki/Reindeer - 06.05.2010
Reindeer
Though Reindeers exist in different colours of coat, such a dark colouration is visible in summer only.