Reindeer
The reindeer (also known as the caribou) is found in large herds in the very north of the world. Reindeer inhabit both the Arctic Tundra and the North Pole regions which include parts of North America, Europe and Asia.
The reindeers hooves adapt to the season so in the summer when the tundra is soft and wet, the reindeers footpads become sponge-like in order to get a bigger surface area on the damp group.
In the winter, the reindeers footpads shrink and tighten, exposing the rim of the hoof which cuts into the ice and crusted snow to stop the reindeer from slipping.