Published November 08, 2009, 12:00 AM

Ask the DNR: Why a deer's coat changes color

The fur coat of a deer changes colors depending on the time of year — a reddish color in the spring and brown in the fall. Why does this happen?

By: Minnesota DNR,

Q. The fur coat of a deer changes colors depending on the time of year — a reddish color in the spring and brown in the fall. Why does this happen?

A. The deer’s coat is designed to provide both a means for thermoregulation and camouflage. Summer coats appear reddish and are thin, allowing deer to better cope with heat stress. In the fall, deer begin a process of molting, which is triggered by hormonal changes that reflect the changing seasons. The reddish summer coat turns into a faded gray or brown color as the new winter coat begins to grow. The new coat comprises two layers. The outer guard hairs are hollow, stiff and grow about 2 inches longer than the undercoat. The inner layer is soft and dense, which insulates deer from the cold weather and snow. Coat color, regardless of the season, tends to be darker in forested areas and lighter in agricultural areas where deer are exposed to more direct sunlight.

— Michelle Carstensen, DNR wildlife health program specialist

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