JACKSON, Wyo. — It has been a cold winter thus far but some of the largest mammals of the west, like bison, have adapted and evolved to withstand the harsh winters.
According to the National Park Service, bison develop thick, woolly coats that help protect them from freezing temperatures and harsh winds. It is said that a bison’s winter coat is so thick and provides insulation so effective that when snow accumulates on its coat, it will not melt from the heat of the bison’s skin.
A bison’s skin also thickens in response to cold temperatures and fatty deposits appear to insulate the animal. During winter storms, bison will turn toward the storm, hunker down, and wait for it to pass. With thick coats and creating a low profile, bison can survive the same storm that would kill many domestic livestock.
Bison also have the ability use their large head and massive neck and shoulder muscles as snow plows to forage in snow as deep as four feet, an adaptation that has helped them survive winters for thousands of years. According to Down to Earth, Nature’s Role in American History, by Ted Steinberg Bison survived the Pleistocene extinctions unlike larger animals like mammoths and mastodons due to their ability to survive on less forage.
Under cold stress, bison have developed the adaptation to minimize nutritional needs and slow their metabolism to conserve energy. Bison slow down the amount of time they spend foraging, and the amount of food they consume in order to conserve energy.
Forage is retained longer in their gut — due to the increase of indigestible plant material found in the winter — which allows them to eat less but still receive the nutrition they require. Without these adaptations, surviving the freezing temperatures and blizzard storms would not be possible.