Animals in Winter

Nature Watch
December 24, 2008
By Susan Benson,CNHM Director of Education

There are worse things than living for days on end with 20 below temperatures, or 40 below windchills. I know it’s difficult to believe, but it’s true. Imagine this instead…

Arctic terns fly 11,000 miles from the north pole all the way to the South Pole.

Deer eat acorns, fungi, and grass in the winter. They browse on basswood, sugar maple, sumac and other trees and shrubs, and they prefer the pencil-sized woody parts of these plants. They also eat 10-12 pounds of this tasty browse per day. I’ll take a hot burger over a basswood stem any day.

Beavers remain active underneath the ice. Back in the fall they were dragging branches of their favorite trees into the water near their lodge. Throughout the winter they swim out their underwater entrance to reach their food cache. Even on the coldest days, their lodge is built so well that it remains at a temperature above 40 degrees Fahrenheit.

Birds just plain shiver in this weather. Continuously. Crows, ravens, chickadees and finches are just a few of the species that shiver consistently.

Many species that are non-colonial during the warmer months will come together and make communal nests during the winter time. Deer mice, meadow voles, and even squirrels are examples. More individuals huddled together create more body heat and also reduces the amount of surface area exposed to the cold.

Honey bees maintain their body temperature through the winter by clustering together in a ball to conserve heat. The bees achieve an average temperature of 64 degrees in the center of the ball and 50 degrees at the perimeter.

Skunks, woodchucks, bats, bears, frogs, turtles, snakes, and other hibernating or dormant animals breathe slowly and lie cold and stiff without eating anything for months.

The wooly bear caterpillar freezes. They produce a substance similar to the ethylene glycol used in automobile antifreeze to protect them from the cold. By midwinter, the amount of glycerol in an insect’s body can amount to 25 percent of its entire body weight.

Whales must migrate as the water freezes so they go to warmer water to have their babies and return with their babies once they have grown.

Finally, if we think we get cold in the winter, we must consider the wood frog. They freeze solid during the winter months. They have no heartbeat. They do not breathe. Their blood does not circulate. Their nerves barely register electrical impulses. Yet their vital organs are not damaged, even after being frozen solid for weeks on end. In the spring, they simply thaw out and hop away to carry on with their day.

So, when we are feeling chilly and tempted to exclaim “I’m freezing,” or “I’m moving south,” both comments I have used in the past few days, remember that there are animals out there that are actually freezing, or dealing with situations I would not trade for anything.

Nature Watch is brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. The Museum invites you to visit its facility in Cable at 13470 County Highway M or on the web at www.cablemuseum.org to learn more about exhibits and programs.