Body Heat

The whole concept of retaining body heat is a fascinating one. Reptiles are cold-blooded creatures and very rarely exist in cold climates (Siberian newt). They have no way of generating body heat for survival and need warm surroundings: exposure to the heat from The Sun and hibernate in cold winters.

Siberian salamander - deep freeze

Mammalian (human) creatures are warm-blooded and this means they are capable of generating the necessary heat internally for body chemistry to function. When a wind (a stream of air) passes over a surface, it removes heat. The use of a coat for humans simply acts as a barrier to retain body heat and slow the loss of warmth from the system.

Warm-blooded creatures are all much the same in this respect.

The natural barrier to heat loss for many mammals is hair growth. This also has a major benefit of minimising heat loss by preventing the wind from contacting the surface in the first place.