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Idaho Fish and Game


Biting cold and driving snow sends most of us indoors to warmth and comfort. Outside, wildlife braves the elements, trying to survive yet another winter. That as many animals survive may seem nothing short of a miracle. But the wildlife that call the Salmon region home have a host of adaptations that help them make it through the year's harshest months. Surviving winter means coping with factors such as temperature, snow depth and density, and the length of the winter season. Some animals simply avoid winter altogether by migrating to warmer climates. Others avoid it by hibernating through the harshest months. The majority of wildlife, however, faces winter head-on relying upon thousands of years of adaptive strategies to survive. The first step to surviving winter's rigors is to go into the winter season in good physical condition. Animals that have found abundant food through the summer and fall months already have the advantage of greater amounts of body fat. This extra fat will provide energy when food supplies dwindle. Storing food in caches is a strategy used by many small animals and birds. These caches are remembered for a surprisingly long time and can be critical to winter survival. Another step toward surviving winter that begins in the late summer is the growth of winter coats. Long hollow outer guard hairs trap air and provide insulation against the cold. The coats of many large mammals such as elk, deer, and moose are so efficient that the animals can actually get hot on warm winter days. Some small mammals such as the snowshoe hare and ermine completely change their coat color to that of white, providing excellent winter camouflage. Birds fluff new feathers acquired during the molt of late summer and early fall; anyone who has worn a down vest understands the insulating value of down! Animal behavior also changes as winter progresses. Elk and deer move to winter ranges where food and shelter are more easily found. Birds that usually inhabit higher elevations during the summer begin to be seen at lower elevations. Wildlife frequent south-facing slopes that are bathed in sunshine for much of the day as well as windswept ridges especially when snow blankets the north and east-facing slopes and valley bottoms. And a general slowing of activity is noticeable as animals move around less and spend more time resting. This is especially true during periods of extreme cold. Many animals both large and small simply stop foraging for food and stay in sheltered areas waiting out the cold. The energy used to find food in such conditions would be more than the energy gained by eating. In such extremes, animals like moose, elk, and deer lower their basal body temperature thus reducing their food requirements and the need to forage. While many animals survive winter some succumb to such things as starvation, malnutrition, disease, predation, and accidents. These are natural factors that have been present among animal populations since winter and wildlife first met. Unnatural factors, however, are becoming a more frequent threat to overwintering wildlife. Disturbance by humans is possibly the greatest threat faced by wintering wildlife. While it can be serious at any time, disturbance is particularly deadly during the late winter and early spring. It is at this critical time that the cumulative effect of winter stresses begins to takes its greatest toll on wildlife. Energy reserves are low and food is not yet plentiful. Even slight disturbances by humans can be enough to cause weakened animals to die. Winter recreationists such as snowmobilers and cross-country skiers are cautioned to give wildlife a wide berth. Try to avoid areas frequented by wintering big game and observe wildlife briefly and only from a distance. If you unexpectedly encounter wildlife, exit the area as quickly and quietly as possible. Under no circumstances should wildlife be chased. The stress caused by just one such incident could prove fatal to many animals in a herd. Such behavior is considered harassment and is against the law; violators will be prosecuted. Be sure to check with the your local Forest Service or BLM offices for travel plan maps. These will tell you if some local, critical big game ranges are seasonally closed to motorized traffic. Winter's snow and cold will soon be gone, replaced by spring warmth and green. Left with their own survival abilities and undisturbed by humans, most wildlife will live see the spring.