What Really Happens To Maine Animals In The Winter?

This story was first published in January 2013.

Frozen trees crack and break. Ice tongues collide.

These are the sounds you hear drifting through the woods of Maine during snowball season. Quiet sounds: snow falls on the ground, mice squeak. This is the sound that shows the silence of the Snow Realm.

What happened to the chatter and chirping that filled the same forest during the summer? How do animals survive the stormy and cold nights?

"If you look, you'll see all kinds of animal tracks," said John Debo, a wildlife biologist with the Maine Department of Fish and Wildlife. "[Winter] is the best time for this. You'll see squirrel tracks, coyote tracks, fox tracks, mink and fox tracks, rabbit tracks, rabbit tracks. Most of our animals don't hibernate.

For many animals, a proper shelter, often with hidden supplies, is key to survival.

Small mammals like mice spend most of their time tunneling through the snow, de Pew said. These snow-insulated tunnels are warmer than the outside.

Beavers spend most of the winter in "houses" made of twigs and mud, feeding on the bark of young trees that they hide underwater during the warmer months. According to Old Town hunter John Meister, hunters can often tell if a beaver lodge is occupied just by placing their bare hands on the fan. When the hot air comes out, the clay stays in the room.

Sometimes, to survive the winter, you need to bundle up to keep warm. For example, common gray squirrels are solitary in the summer, but in the winter, they usually bite into a ball and hide with other squirrels, according to Peterson's Field Guide to North American Mammals.

But simply blocking is not the same as hibernating.

“Sleep is basically when an animal’s breathing slows and its heart rate slows. You can’t wake a creature from sleep. It’s a state of suspended animation,” said Lisa Kane, a wildlife educator at DIF&W.

According to Kane, only three Maine mammals are "true hibernators"—badgers, prairie hopping mice, and bats—that congregate in winter caves to "hibernate" in the fall.

And what about bears, which most people think of as hibernating animals?

Biologists call black bears "part-time sleepers."

"It's a very common misconception," Kane said of bear hibernation. "You can wake the bears up. When all our biologists go to their dens for the winter, the mother bears are awake...they don't eat or drink, but they don't fall into that deep sleep either. Get up and walk around."

Other part-time species are raccoons, porcupines, and skunks.

“So we have awakes, these are very technical terms, and they are basically predators, coyotes, foxes, coyotes, cats. They stay awake all winter and look for food,” Kane said.

Many of these birds of prey have evolved a form of walking called "perfect gait", in which their hind legs sit in the tracks of their front legs, reducing the animal's energy to move through the snow.

The most common tracks in the winter are "smart" non-predatory ones such as white-tailed deer, rabbits, and hares. However, the forest often appears eerily quiet and peaceful, as if the animals whose tracks have been left behind have disappeared.

Sometimes you might hear a woodpecker or the crackling of a nuthatch, see the movement of a turkey circling a snowdrift, or see the movement of an eagle soaring overhead. Although many of our birds have flown south, some species remain and tolerate the cold.

"The earliest nesting bird we have is the great horned owl," Kane said. "By the end of this month, he'll start yard work and nesting and they'll have babies by mid-February. By early March the youngsters will be begging for food. People describe it as killing someone in the middle of the woods."

Besides birds, frogs are the main source of sound in Maine.

In elementary school, children learn that frogs and turtles burrow into the mud at the bottom of ponds and streams in the winter and come out again in the spring. But it is not easy to understand how this is possible. How do they breathe?

As it turns out, the answer isn't quite so simple.

According to American Rick Emmer, chief rainforest scientist at the Cleveland Metroparks Zoo, turtles make their winter beds in the mud. During hibernation, the turtle's metabolism slows enough to survive in the mud with a small amount of oxygen.

Water frogs will suffocate like a Maine cobra.

According to Emmer, frogs try to keep their body parts away from dirt so they can access oxygen-rich water. They can sometimes swim slowly. So if you look down through a thin layer of ice and see a frog gliding across the icy water, don't feel bad about it. There is air in it. It's just a change of sleeping position.

Maine ground frogs, like spring toads and toads, overwinter in the ground. Frogs burrow in the ground below the frost line, but tree frogs like toads don't dig well, so they just find a nook or crevice to hibernate.

The tree frog's body often freezes. Ice crystals formed under his skin. His breathing would stop and even his heart would stop. But he didn't die. Why? The high concentration of glucose in the frog's vital organs prevents freezing. When spring comes, the frog molts and its heart and lungs start working again.

In addition to seeing plenty of frogs on summer hikes, you can usually spot some laced snakes basking in the sun along the way. And since these snakes live for several years, where do they go in winter? They certainly don't slide south.

According to the National Audubon Society's Field Guide to Reptiles and Amphibians, northern garter snakes hibernate in communal burrows, often under large rocks or inside mammal burrows. These particular snakes tolerate the cold so well that they usually appear in early spring and can even be seen traveling through the melting snow.

What did they learn from the Encyclopedia of Animals and Biologists? Humans may be the noisiest animals in the woods, crushing snow on plastic and metal snowshoes, but they're not the only ones.