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Since this column is being sent in before Groundhog Day, I have no idea whether the groundhog will see his shadow or not. Therefore, I'm going out on a limb to predict that we are going to have either six more weeks of winter or 42 more days of winter.
An early verse for February second, which is also known as Candlemas Day, went like this:
Half the grain and half the hay
Half the winter is passed away
We eat our supper by the light of day.
The meaning of this old verse was important to our early ancestors. If a farmer still had half of his hay and grain by the second of February, he would be able to make it through to spring; however, if over half of the supplies put in for winter were used by the second, the family would be in trouble. The family gathered together for supper at five o'clock, and by February second, there would still be daylight while they were eating. What is important to me is whether our woodshed is still half full of firewood by the second of February.
This column is about the animals that sleep the deep sleep, the hibernators. Pennsylvania has seven heavy sleepers, and they are the woodchuck, chipmunk, three species of bats and two species of mice. A few insects, turtles, frogs, toads, snakes and snails could be added to this list.
To be considered a true hibernator, the body functions of the animal must drop drastically, with breathing becoming very slow and shallow. For instance, while hibernating, a woodchuck will take a breath every four to six minutes, and a jumping mouse might only take a breath every 15 minutes. The body temperatures of both animals will drop to right above freezing.
Some bats are true hibernators. I use the word "some" because there are bats that will migrate instead of hibernate, while others migrate and hibernate. However, when in hibernation, the bat's body temperature usually coincides with the temperature (usually 50 to 60 degrees) of the area where the bat is hibernating.
When in hibernation the animal's heart beat slows, with very little blood circulating within the body. There would be a minimal amount of bleeding if a toe was cut off a hibernating animal.
To prepare for the harsh winter months, some animals put on an extra layer of fat to help them survive. These animals, which are not true hibernators, are known as the "light sleepers." On warm winter nights, these light sleepers sometimes leave their dens and move about in search of food. During periods of cold weather that could last for days or weeks, these light sleepers will den up, become inactive and live off their stored body fat.
Wildlife biologists know that these hibernators put on layers of fat to help them make it through the winter months. If all of their body functions slow down, why do they need this fat?
The woodchuck puts on fat but uses very little during hibernation. It's not uncommon to see a woodchuck's tracks in the snow at this time of the year; however, we all know that during the late winter, there is very little for the woodchuck to eat, and this is when the chuck uses up much of its fat reserve.
Of course, some hibernators use their body fat during hibernation. When cold creeps into the den or crevice, the animal's body must react to keep its temperature just above freezing, and this is done by shivering. Shivering produces heat, which raises the body temperature and uses up body fat.
During an especially cold winter, some hibernating animals die because they run out of their stored fat because of shivering too much.
The chipmunk does not put on a lot of body fat to go into hibernation. Instead this small animal stores food and wakes up for a snack every few days during the winter months.
Studies have shown that hibernating animals do not go into hibernation with full stomachs. Immediately before going into hibernation, the animal goes into a fast.
The stomach will be emptied and intestines purged until clean.
It appears this must be done because during hibernation, body functions, such as digestion of food, will not work.
While in hibernation, frogs and turtles actually freeze solid by producing a substance known as glucose, which protects the body's cells against ice damage.
If we humans were to pump this much glucose into our bodies, we would go into diabetic comas and die.
Frogs and turtles receive their needed oxygen from the cold water. Although they do not breathe, oxygen is taken in through the skin.
For example, after going into hibernation, the common painted turtle does not take a breath for the next five months and its heart beats only one beat every 10 minutes.
During this slowdown of body functions, the body builds up with lactic acid, enough to be lethal; however, the turtle combats this by using a chemical (calcium carbonate) found in its shell. This compares to us humans taking antacids.
Perhaps a day will come when man will unlock more of nature's secrets; but for now, the more we learn about the animals we share this planet with, the more we have to marvel at their abilities.