Coping with the cold clutch of winter

December 12, 1996|By BARBARA TUFTY

WASHINGTON -- Now in December as the Northern Hemisphere tips away from the sun, the long oblique sunbeams offer little warmth and brightness to the land. Winter darkness spiked with frost creeps across desolate fields and filters through naked deciduous forests.

Summer's bright flowers have long since withered, and the few autumn leaves that still cling to the oaks have relinquished their copper and bronze color for a somber brown. The buzzing and rustling racket of the natural world quiets to a whisper as its inhabitants move away, sleep or slow down to cope with the cold clutch of winter.

To escape the frosts and snow, some animals walk, fly, swim to warmer regions where food and sunlight are more abundant. Far to the north, moose and caribou wend their way southward through deep snow, moving from frozen lands to places where they can find water and succulent twigs. From the chilled north Atlantic Ocean, right whales migrate south to

Barbara Tufty

warmer seas; while the blue crabs of the Chesapeake Bay dance on tiptoes toward the southern end.

Swallows and warblers, flycatchers and swifts have flown south, and geese and swans spread long lines across the skies as they seek southern sanctuaries. Ducks, rails and teals take water routes south, and sandpipers and plovers follow the sandy edges of the ocean.

Other animals come to terms with winter where they are. Mice and voles stay snug in tunnels beneath snow and dead grasses where they run hidden from the eye of hawk or jaw of fox. In the frozen fields and woodlands, chickadees, titmice and woodpeckers plunder dormant insects and left-over berries of verbena and bittersweet or seeds of ragweed and Queen Anne's lace. Bright flashes of cardinals and bluejays liven the somber landscape, while starlings bunch together in noisy flocks, and black-robed garrulous crows congregate to discuss the evening news.

Searching the abandoned orchards

Wolves, coyotes, bobcats and other members of the canine and feline families insulate themselves from winter winds with thickening fur, and pace through the woods at dusk to track their prey -- the nervous white-tailed deer searching for frosty apples in abandoned orchards.

Bears, skunks and raccoons stuff themselves on autumn nuts and berries and take long winter naps in caves and hollow trees, shuffling out on occasional sunlit days in search of a snack.

Chipmunks, woodchucks and ground squirrels fall into a deep near-death sleep called hibernation that carries them through the cold winter into spring. Now their body temperatures drop, and their circulation and respiration seem almost to stop.

Cold-blooded reptiles and amphibians have different strategies for survival. Since their body heat depends almost entirely on surrounding temperatures, when the air gets colder so do they. Snakes twine around one another in pits and become immobilized in freezing temperatures. Toads and turtles dig themselves into the earth below the freezing zone, and wood frogs and spring peepers, much like certain insects, produce an antifreeze chemical in their bodies that prevents deadly ice crystals from forming.

And so while we humans turn up the thermostat and don insulated parkas and boots, each species of the natural world uses its own ancestral method to survive the cold dark winter.

Barbara Tufty is a science writer and consultant.

Pub Date: 12/12/96

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