Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, January 9, 1994 TAG: 9401080018
SECTION: EXTRA PAGE: 5 EDITION: METRO
SOURCE: Patricia Held
DATELINE: LENGTH: Medium
I think that the smartest animals are those that avoid winter by disappearing into the earth. They simply nod off into a very deep sleep or state of suspended animation called hibernation.
In our area, some insects, amphibians and reptiles, and a few mammals go into a period of extreme inactivity. Among local hibernating mammals are the bat, woodchuck or groundhog and both the meadow and woodland jumping mice.
There are advantages to hibernation. Little energy is expended to stay warm. Animals do not have to waste any effort in search of food. Since they need little food to stay alive, they survive on the small amount of stored energy.
While some animals escape the weather by migrating or hibernating, some not only tolerate the harsh winter environment but take advantage of it.
Many animals seem undaunted by winter's arrival. Their heavy fur coats enable them to maintain a relatively constant body temperature. In preparation for winter's chill, a mammal's coat thickens. Some even have an extra layer of waterproof covering over the dense, woolly underlayer. Muskrats, otters and beavers have this outer waterproofing of long, oily hairs. This double coat traps air between surfaces and retains heat.
Furry tails are wonderful protectors against the cold. When a fox or squirrel sleeps it curls its long furred tail over its nose and face. This makes a warm air chamber, and as air is drawn through the animal's bushy tail it loses its stinging cold bite.
Birds that choose to winter here seem to cope well. They feed on seeds left over from the previous season, and they know where to find insect eggs and larvae to keep themselves well-fed. They fluff out their feathers and enlarge the dead-air space around their bodies, thus building a barrier against the cold. Water birds keep paddling to keep the water churned, so it doesn't freeze around them.
A decrease in surface area lessens heat that is lost by radiation. So there is a tendency for animals in very cold climates to have smaller external features such as ears and tails.
Small animals have a tougher time staying warm than large animals. It is more difficult for them to retain heat because of their high ratio of surface area to body size. To compensate, small animals burrow into the snow to escape the cold. Snow acts as a natural insulator and provides a safe shelter for the animals. Air is trapped between the snow crystals and protects the ground from chilling temperature above.
Location is important to an animal trying to stay warm. Just watch a cat as it returns again and again to a certain spot at the same time each day. Usually it is where the sun is the strongest and it can bask in its warmth. Other animals do the same and will often construct their homes to face the sunniest location possible.
Leaf cover and rotting logs make excellent places to hide and keep warm. Heat is generated by decaying leaves, and rotting wood is sufficiently warm to keep insects and small animals warm enough to make it through the winter.
Herd animals, such as deer, cattle and horses, conserve heat by standing together in tight groups. As the herd breathes and respires, moisture is held above them, and warmed air is retained below the herd.
One of the biggest problems for animals is obtaining food. Some stock up on supplies for winter and rely on their caches when sources become scarce. Many animals can survive lengthy periods of fasting by relying on reserves of body fat. But most importantly, those that survive the winter must have flexible diets and be able to adapt readily to whatever is available.
When the weather becomes extreme, such as in heavy snow and frigid temperatures, most animals find shelter. Although winter can be a difficult time for some animals, a variety of wildlife can be found up and about during the season.
Take advantage of the winter months and look for tell-tale tracks in the frozen mud or freshly fallen snow.
\ Patricia Held will respond to readers' questions on the plant and animal wildlife in the region. Mail inquiries to: Patricia Held, P.O. Box 65, Goode, Va. 24556.
\ Patricia Held is a Bedford County free-lance writer and author specializing in natural history.
by CNB