Winter is the most stressful time for big game in Wyoming. Low temperatures mean animals must expend more energy to maintain body heat. At the same time, the plants they eat are lower in nutrients than they were when they were green and growing, and are often under deep snow. During winter, big game seek out habitats with features that give them a fighting chance: less snow depths, vegetation cover that gives some protection from the elements, and plants like shrubs with higher nutritional levels. However, even with relatively good winter habitat, animals are typically on a weight-loss trajectory that only ends when spring green-up begins.
As important as winter habitat is, however, much of what determines if an animal survives actually occurs before winter storms hit. During summer when an animal is feeding on green, succulent plants, its energy intake exceeds its energy demands and that energy is stored as fat, often as much as 20 percent of its body weight. During winter, when energy demands exceed energy intake, that animal draws on those fat reserves to maintain body heat. Survival, then is as much or more a matter of the quality of that animal’s habitat during summer than winter. Fall precipitation that result in plant green-up, as was seen in much of western Wyoming this year, can be a real boon to big game as it creates an opportunity for even greater fat reserves going into winter.
As important as winter habitat is, however, much of what determines if an animal survives actually occurs before winter storms hit. During summer when an animal is feeding on green, succulent plants, its energy intake exceeds its energy demands and that energy is stored as fat, often as much as 20 percent of its body weight. During winter, when energy demands exceed energy intake, that animal draws on those fat reserves to maintain body heat. Survival, then is as much or more a matter of the quality of that animal’s habitat during summer than winter. Fall precipitation that result in plant green-up, as was seen in much of western Wyoming this year, can be a real boon to big game as it creates an opportunity for even greater fat reserves going into winter.
Publish Date
Answered By
Jerry Altermatt
Job Title
Terrestrial Habitat Biologist, Cody Region
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Ask Game ID
67
Node order
238
Parent Node
1135