Black-capped Chickadees are a wintering bird whose brain adapts by enlarging the memory portion of the brain.
Although we have had a relatively mild fall season in the Edmonton area this year, all animals have to adapt to the eventual cold and snowy conditions of winter one way or another. There are several ways of doing so:
- Migration – instead of actually adapting, some animals leave an area with unfavorable conditions for a warmer or more suitable climate and conditions. Migration is commonly known among bird species such as ducks and geese that need open water in order to find aquatic vegetation, or smaller songbirds and tree swallows that feed on live insects. Warmer weather can delay when migration actually occurs, however, the conditions will eventually change. Some mammals, such as caribou, although well adapted for winter, also migrate to wintering grounds that provide better shelter. Monarch butterflies travel thousands of kilometers from Canada to their wintering grounds in California and Mexico.
- Some form of hibernation – retreating to a sheltered area and going into varioius physical states for different periods of time depending on the conditions.
- True hibernation involves a decrease in breathing rate, activity level and heart rate, all contributing to minimal energy consumption, and a deep sleep which can’t be disturbed. True hibernators include bats and groundhogs.
- Torpor is a lighter type of hibernation with animals waking occasionally during warmer weather. Bears and striped skunks are examples of animals that go into torpor, with a lower heart rate but maintaining a higher body temperature. I have personally had the surprise of seeing a skunk wandering in front of our home in Edmonton in February, thanks to our dog detecting its’ scent!
- Brumation is like hibernation but applies to cold-blooded animals such as reptiles and amphibians which may wake up to move and drink water.
- Physical changes and behaviours that allow the animal to remain active during the winter:
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- Changes to fur thickness and colour – snowshoe hares grow a thicker coat that changes colour from mainly brown to mostly white which provides camouflage from predators.
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- Black-capped chickadees who eat seeds all year-round, can puff their feathers so that more air is trapped between them, acting as insulation against the cold. Amazingly, in the fall and winter, the hippocampus portion of their brain enlarges to allow the chickadee to remember where it stored its’ food supply.
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- Using snow for shelter – Ruffed grouse dive into fluffy snow for warmth and will often surprise a winter hiker by bursting out of it just in front of them.
Whatever your chosen winter activity, hiking, skiing or snowshoeing, you’ll have plenty of opportunity so see animals who are active during the winter and observe how they have adapted to their environment!
Source: Nature Canada