Winter Survival#

Animals have evolved life-preserving strategies to survive cold winters. The following is a list of some native animals and how they survive.

1. What are mammals and how do they survive the cold winter months?

   • a. Mammals are warm-blooded animals (endotherms) in the subphylum vertebrata. Two characteristics that set mammals apart from other organisms are hair or fur covering parts of their body and mammary glands that provide milk for their young.
   • b. Hibernation in most animals is a seasonal period of adaptive torpor that allows the animal to survive regularly occurring seasonal change. Massachusetts only has three “true” hibernators: the woodchuck, meadow jumping mouse, and little brown bat.
   • c. Torpor is the dormant, inactive state of a hibernating or aestivating animal.
   • d. Fur color gradually changes from a fall brown to a winter white in snowshoe hare, long-tailed weasel, and ermine. The new white coat works as camouflage to hide the animal from would-be predators.
   • e. Fur becomes thicker in winter to help red squirrels reduce heat loss.
   • f. Warmth in numbers is how flying squirrels survive winter cold. They huddle together in tree cavities and use their body heat to keep warm.
   • g. Microclimates are created when gray squirrels build nests in tree branches or in a tree cavity. The dried leaves of deciduous trees are water resistant and keep them dry.

2. What are amphibians and how do they survive the cold winter months?

   • a. Amphibians are cold-blooded animals (ectotherms) in the subphylum vertebrata. Frogs and salamanders have smooth, usually moist skin. Most amphibians lay their jelly-like egg masses in water.
   • b. Brumation is the cold-blooded animal’s version of hibernation. Amphibians cope with cold winter temperatures by settling in a pond (bullfrog), under leaf litter (wood frog) or entering underground tunnels on land (American toad).

3. What are reptiles and how do they survive the cold winter months?

   • a. Reptiles are cold-blooded animals (ectotherms) in the subphylum vertebrata. Reptiles have scales and sometimes bony plates covering their bodies.
   • b. Brumation is the cold-blooded animal’s version of hibernation. Reptiles cope with the cold winter temperatures by settling in a pond (snapping turtle) or entering underground tunnels on land (garter snake).

Good winter ecology resources:

• Heinrich, Bernd. Winter World: Harper Collins Publishers, New York, New York, 2003.
• Stokes, Donald. A Guide To Nature In Winter: Little, Brown and Company, Boston, Toronto, 1976.