Caribou are the only deer in which both sexes grow antlers. Antlers of adult bulls are large and massive; those of adult cows are much shorter and are usually more slender and irregular. Adult bulls average 400 pounds. However, weights of 700 pounds have been recorded.
Caribou are also characterized by making long migrations, traveling further North during the summer months for fresh grazing and returning to the more temperate climates of the South in the winter for shelter. The complete migration sees caribou herds traveling as many as 1,600 miles each year.
Caribou hooves are large and sharp enabling them to travel large distances as well as making them efficient swimmers. The caribou family also includes the elk, moose, reindeer, and deer.