Wildlife Wednesday - Goosebumps

By Andy Ames

A sudden chill often gives us “goosebumps”. “Goosebumps” form when tiny muscles at the base of our hair follicles contract and raises our hairs. Birds and many mammals have a similar response to cold temperatures. The fluffing of the feathers or raising of hairs helps opens up pockets of air that can trap heat close to the body. Insulation is the name of the game for winter warmth. Contrary to popular belief, coats, or feathers or fur as the case may be, are not intended to keep the cold out but help keep our body heat in. At a distant time in our evolutionary history we also had enough body hair to trap body heat. Now, however, when we feel the chill, we can pull on our own down coat.

See below to learn how this reflex helps our local wildlife stay warm on the coldest days.

Dusky grouse are masters at staying warm. Downy under feathers are all fluffed up with the outer feather forming a tight shell. Its feet are tucked neatly under its body, with its overall shape forming a sphere to minimize surface area. In severe conditions they will bury themselves in the snow for an extra blanket of insulation.

This Mountain cottontail takes a similar approach to the grouse. Head tucked close to the body with feet tucked underneath, this rabbit also forms a sphere. While it doesn’t have downy feathers, its soft fur traps air to prevent heat loss.

On cold days you will see deer and other animals puffed up, too. Like a down coat, these raised hairs trap warm pockets of air close to the body.