Moccasins are a form of shoe, boot, or slipper constructed from the skins of animals such as caribou, deer, moose, elk, and bison in the past. Indigenous peoples constructed moccasins with soft soles to fit easily into snowshoes in locations with harsh winters, such as the Subarctic. Indigenous peoples on the Plains, on the other hand, added firm soles to their moccasins to aid walking over rocky terrain.