If you’re like me, sometimes, on a cold winter day, I just want to ‘hibernate’ – to stay in my warm bed and let the world go on without me. Can you imagine doing that for four to six months of every year? In today’s post, discussion turns to many animals who prefer hibernation rather than a miserable winter of food shortages and freezing weather.
During the deep sleep of hibernation, the heart’s pulse rate slows to a minimum, dropping the metabolic rate about as low as it can go. In this state, daily food and water are not needed, the animal uses reserves of stored fat for nutrients.
Reptiles and other cold-blooded animals must bask in sunshine to maintain their body temperature. In the winter, they keep to their dens deep in the banks of rivers and creeks, or far below desert sands.
Only the fertilized queens of social insects, like wasps anbd bees, survive the winter by hibernating in crevices and outhouses. All the workers are killed by the first frosts, but the queens emerge in spring to found a new colony.
The woodchuck, a North American ground squirrel, sleeps for eight onths of the year, emerging in February.
The most important autumn task for hibernating animals is to eat continually, accumulating enough fat energy reserves to last until spring. Golden hamsters store caches of food before sleeping, so that a convenient supply is avalable when they awaken.
Red squirrels may break hibernation and forage if the winter conditions are mild, digging up nuts that have been buried in autumn.
Squirrels hibernate in secure nests constructed from twigs in the branches of a tree, wrapping their bushy tails around themselves for extra insulation against the winter cold.
Three-toed terrapins burrow into the mud around ponds during the winter.
Shelter and security are the key criteria for choosing a hibernation site. Bats and bears sleep in dry caves. Bats hibernate communally, packed together for mutual warmth.
Only the slow, rhythmic rise and fall of the rib cage and a gentle snoring show that hibernating bears are sleeping, and not dead.
Winter is a good time to search for hibernating butterflies in old buildings, roof spaces and outhouses, where they may emerge on occasional sunny days. Provide these early risers with a piece of cotton wool soaked in dilute sugar solution, so that they can replenish their energy supplies before settling down again to sleep through until spring.