Caribou are large, wild, elk-like animals found in Arctic North America from Alaska to Greenland. In northern Eurasia, the same species (Rangifer tarandus) is semi-domesticated and they are called "reindeer".

Caribou and reindeer are the only deer where both cows and bulls have antlers. The large antlers of a mature bull can reach 4 feet / 1.2 meters in width, but they're shed in early winter. Cows keep their antlers until calving time in June, and that formidable "rack" allows them to claim and defend the best feeding areas in late winter when they need high quality food. Remember - pregnant cows are eating for two!

There are three types, or subspecies, of caribou with matching groups for reindeer:

1. Peary caribou / Marine reindeer: This small caribou is the least plentiful. They spend the entire year on the treeless tundra or islands near the Arctic coast.

2. Barren ground caribou / Tundra reindeer: The most plentiful and the ones forming the large herds that each year migrate between the treeline and coastal plains.

3. Woodland or mountain caribou / Forest reindeer: They do not form vast herds or make extensive migrations. Instead, they form smaller groups that move between the northern forests and open mountains.