Caribou, or Reindeer as they are also known, can be found across the northern reaches of several continents. In Alaska they range from the Aleutian Islands to the Arctic Ocean. Their primary diet consists of lichens, which they digest in a series of four stomachs, but they also browse on other ready plant sources and have even been known to eat lemmings, arctic char, and bird eggs. Caribou sometimes travel alone but it is much more common to see them in group that range from just a few to several thousand. If you chance to see a caribou close-up, listen closely for the characteristic popping that is produces by tendons sliding over its leg joints.