February and March are the months with the highest mortality rates among wild animals, according to James Eyring, assistant director of the Pace University Environmental Center in Pleasantville, N.Y.
Eyring says that as food and fat reserves run low, "Only the strongest will survive."He says there are four ways that animals adjust to winter - insulation, adaptation, hibernation and migration.
Deer, for example, grow a long coat of hair in autumn. Each strand is hollow, trapping a layer of air for warmth. Deer also sleep on the southern slopes of ridges to catch the sun's rays.
Ruffed grouse adapt to winter by growing appendages on their feet that serve as snowshoes. They sleep after flying head-first into a snowbank that acts as an insulator.
Honeybees adapt to winter inside a hive, eating honey and vibrating their wings to generate a steady temperature of about 80 degrees F. They winterize their hive by caulking it with beeswax, except for small fresh air exchanges.
"If there are three or four days of warm winter weather, the bees will have a cleansing flight where they leave the hive to release their excretions and remove any dead bees," Eyring says.
Hibernating slows the animals' body functions. Not only do fur-bearing animals hibernate, but so do reptiles. Eyring says snakes and land turtles spend the winter below the frost line where their body temperatures lower to about 45 degrees F. Water turtles winter at the bottom of a pond, breathing through an anal vent.
"This water circulates through the turtle's intestines where oxygen is absorbed, similar to a primitive gill," says Eyring.
Many species of birds and fish survive the winter by migrating to warmer environs.
Animals who must weather harsh winters, such as grouse, rabbits and deer, eat tree buds and drink sap for the sugar and carbohydrates needed to produce fat.