Subnivean inhabitants build tunnels under the snow, but come up occasionally to look for food. Here are the tracks of a mouse as it jumped across the top of the snow.
Animals in Winter
Animals, like people, have many different ways of preparing for and surviving the cold winter season. One way is to avoid the cold altogether. Migration is a strategy used by birds, bats, and insects where they move to warmer areas of the United States, Caribbean, and Central America. In these places they will have plenty of food and will not need to worry about cooler temperatures.The Monarch Butterfly, Vermont's state butterfly, is one of the insects that will travel south, often as far as Mexico, to escape from the cold weather. You can expect to see many of these animals again in the spring as they make their return trip back to their summer grounds.
Animals that cannot migrate must stay and adapt to tolerate the colder climate here in New England. But some animals that stay in the area evolved special strategies that have enabled them to stay inactive and save energy during the coldest of winter months. This is called hibernation or torpor, where animals often experience lower metabolism and a lower body temperature. Bears, woodchucks, and squirrels are some of the animals that will spend much of their winter living off stores of food they have collected or stores of fat they gained during the summer months. But this sleep is not really sleep at all, instead an animal's body will slow and much of the active body processes will shut down for a while. Occasionally, these animals will wake up during warmer winter days to come out of their burrow and dens to feed. Surprisingly, these animals will also wake up from hibernation on warm days only to get some real sleep; beneficial sleep, which can repair brain tissues in mammals, needs active metabolic processes that are shut down during hibernation.
Some animals remain active all winter despite the snow on the ground. Animals like deer, weasels, rabbits, foxes, coyotes, mice and voles have tricks to find enough food and stay warm during even the coldest parts of the year. These animals have high body temperatures and metabolisms. Mice, voles, and moles are subnivean, which means they live below and underneath the snow. Here, below the snow and ice, it can be up to 50 degrees warmer than the outside air.
Animals like deer can't live under the snow like mice, but they do find deer yards; areas under coniferous trees that are protected from heavy snow. Deer also make pathways through the snow, using them over and over again so they can save energy by avoiding the deepest snow. Coyotes and foxes use their good sense of hearing to hunt for mice in their tunnels under snow packs. The short-tail weasel and eastern cottontail rabbit replace their thin brown summer coats with almost entirely thick whites one, so that they can better blend in with their snowy environments and stay warm.