Humans have it easy compared to animals' remarkable adaptations to the harsh realities of winter
by Ward Cameron
There's always something magical about winter: The sudden proliferation of white...the crispness in the air...the glint in the trees as the sun reflects off individual snow crystals. This winter seems to be all over the map - from frigid temperatures to freezing rain. While most of us are simply trying to deal with the many challenges that these weather fluctuations bring, the area's wildlife spent all last summer preparing for the long winter - and these signs are also visible.
I've always felt that once the colours of autumn are gone, we might as well have snow. The intervening weeks between leaf fall and the start of winter are often filled with the anticipation of a long ski season. For the area's wildlife, the anticipation is also present. With the exception of our Mallard Alley residents, most of the area's birds make their way to warmer climes.
A few of our more hardy birds stay in the area year-round. Birds like the Canada Jay provide a pleasant diversion on a cold winter's ski. It's not uncommon to have them land on your ski pole during your lunch break. Remember though, their natural foods are much healthier for them than peanut butter and jelly -even if it's on whole wheat. With warming climates and the increases in the number of bird feeders across the west, we're seeing more and more birds sticking around for the winter. It is becoming less uncommon to see hawks and the occasional eagle during even the coldest winter months.
Some local residents have another way of dealing with the winter - they just sleep through it. The area's ground squirrels head into their burrows for the duration. Once into hibernation, their body temperature drops to just a few degrees above freezing and their breathing rates to only a few each minute. This slowing of the metabolism allows them to survive the eight or nine months of winter without eating a bite.
Bears head into their dens once the snow flies, but it's debatable whether they actually hibernate or not. Their winter rest is more akin to a deep sleep than true hibernation.
Bears also head into their dens for the winter. There is some debate whether or not they can be considered true hibernators, however. Their winter's rest is more akin to a deep sleep. They may occasionally wake up, but very rapidly head back to bed. Their body temperature and respiration do not drop as drastically as in the case of ground squirrels and other hibernators. For example, a bear's body temperature drops to about 34°C from 38°C compared to the more marked decrease in the ground squirrel. Their respiration and heart rate also drop only slightly below normal. Essentially, they need almost as much food energy every day they spend in the den as they would were they up and active.
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A Richardson's Ground Squirrel enjoys a summer day and the bounty all around before heading underground to its den for a winter spent hibernating.
Some animals, like the pika, stay active throughout the winter. Having spent the summer collecting plants and placing them into huge haypiles, they use these reserves to get them through the winter months. These piles, which can contain upwards of a bushel or more of material, will supply the pika with the better part of a year's worth of food. Pikas live only in the higher alpine areas, so summer is very short and winter very long. Needless to say the summers are spent madly collecting stores for the following winter.
Mice and voles also remain active during the winter. Their small bodies are only capable of producing small amounts of heat and they lose that heat rapidly when exposed to cold winter temperatures. Their strategy is to stay active beneath the winter snows, traveling in tunnels beneath winter's white blanket. This under-snow world is referred to as the subnivean environment. Slightly larger animals like the marten and weasel will spend portions of the winter in both worlds, above and below the snow. They will do some of their hunting exposed to the winter elements but will retreat beneath the snow to both escape the cold temperatures and hunt some of the small animals that attempt to hide out in the subnivean.
Larger animals are able to produce more heat, almost like having a large furnace. At the same time they lose that heat much more slowly than smaller animals. This enables them to stay active above the snow during the winter months. They collect in areas that provide a good combination of cover and winter food. Highwood Pass in the Kananaskis is closed from December 1 to June 15 as it provides one of the best winter ranges around. The high slopes of the pass are heavily windblown, which keeps them free enough of snow for the animals to graze. During hard winters, elk will eat the bark of aspen trees. The scars left behind are a common sight on the area's aspens.
Everywhere we look around, the signs are there. The mountain environment requires both animal and man to adapt to the challenges of a mountain winter.
Ward Cameron is a Canmore-based naturalist, photographer and author. His Web site, www.mountainnature.com, is an on-line guide to the nature of the Rocky Mountains. His popular guide book, Canmore & Kananaskis: Best Hikes, Best Activities, includes hiking trails, popular attractions, historical vignettes and superb colour photography.
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