Winter in Alberta (Photo by Jenel Bode)

Winter in Alberta (Photo by Jenel Bode)

How animals survive Canadian winters

The hump on a grizzly bear's back is a huge muscle (Photo by Getty Images)

The hump on a grizzly bear's back is a huge muscle (Photo by Getty Images)

Most of us know that birds migrate south to escape Canada's harsh winters while small mammals hibernate, but what happens to the insects and amphibians that stay during the wintertime?

During hibernation, mammals slow down their heart and breathing rates to conserve energy. They enter hibernation because there is little to no food during the winter, while birds such as Canada geese migrate south to areas with food and ideal breeding conditions.

A common misconception is that bears hibernate during the winter. Due to their large size, bears cannot lower their body temperature like smaller mammals, so they enter a lighter state of sleep, called torpor. During torpor, their heart and breathing rates fall to save energy. However, they are still able to wake up during the day and move around to defend their cave.

Unlike mammals, insects have a variety of ways to deal with cooler temperatures. One common way is for adult insects that live less than a year to bury their eggs underground before dying off. When spring rolls in, the eggs hatch and the cycle continues.

However, insects such as beetles and wasps are able to survive because their bodies produce a natural antifreeze protein. This protein lowers the freezing temperature of the insect's bodily fluids and stops harmful ice crystals from forming. Freeze-resistant insects include many species of moths, butterflies and beetles.

Similarly, amphibians, such as wood frogs, produce antifreeze proteins. Unlike toads, who dig down into loose soil and enter a state of dormancy, these little critters are not adept at digging and instead seek out cracks or crevices in logs or rocks or just bury down into leaf litter. When temperatures fall below -5 C, a wood frog’s natural antifreeze will prevent it’s organs from freezing, even though they breath or have a heart beat. Once spring rolls in, the frog thaws, and continues with its activities.

Like toads, insects such as ants can also enter a state of inactivity where they eat excessive amounts of food before winter and lower their heart and breathing rate to conserve energy. However, not all insects are dormant during the winter.

Bees do not sleep during the cold months; they stay in their hives over the winter. To keep the hive warm, bees will gather around the queen and vibrate their wing muscles. With so many bees vibrating their muscles at the same time, the centre of the hive warms up to a comfortable 33 C.

It is amazing how animals have developed so many unique methods to survive the harsh Canadian winters. Next time you go on a walk or sit in your backyard, take the time to observe the species around you and ponder on how they survived during the winter.

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