Answer: Insulation.
Explanation: Insulation can be defined as the protection against the changing or different environment. Insulation is usually seen the animals living in polar regions.
The fur helps in sustaining the internal heat of the body to remain inside the body without being lost outside due to the colder environment outside.
The Eskimos experience one of the world's extreme winter climates and in this kind of a situation caribou's coat provides insulation from cold.