By Bill Lawyer
Every year around late fall and early winter, many people in the northeastern United States start thinking about hibernation. Maybe they think it would be nice if <they> could hibernate. They wonder how it is that some animals do hibernate, while other, seemingly similar animals don’t.
Wouldn’t it be nice if we could just go to sleep after Christmas and wake up the first of April? No worrying about driving on snow and ice, no having to go to work or school and back all bundled up in the dark.
Until the advent of electric lights, the long winter nights were very conducive to getting into bed and staying there.
While scientists have been studying hibernation for many years, once the Space Age dawned they focused their attention on human hibernation, in case astronauts needed to hibernate for long periods of time — in between habitable planets.
Rye pediatrician Bruce Reidenberg points out that for many years a very brief version of hibernation has been used to shorten the length of surgical procedures.
The extreme version of this is cryogenics — freezing people in a near-death state until a cure can be found for their disease.
First, let’s clear up what kinds of animals do or don’t hibernate. The Elementary Science Program offers some information on this topic. Among the mammal hibernators in New York State are black bears, groundhogs, jumping mice, and some bats. Many other animals also hibernate, including turtles, frogs, salamanders, and snakes, as do some fish and insects. Carp cover themselves with mud and sleep at the bottom of the pond. Woolly bear caterpillars hibernate as larvae, cecropia moths do so as pupae; and the mourning cloak butterflies as adults.
Some animals go into deeper hibernation than others, and scientists are still trying to determine why these variations occur.
Hibernation occurs when an animal lowers its metabolic activity rate — slowing heartbeat and breath rates, and the like. A popular phrase for this is “suspended animation.”
As life on earth’s landmasses evolved, a wide range of hibernation techniques occurred, depending on minute changes in climate, as well as more drastic changes, during the various ice ages.
Whereas some species migrate to warmer climates, others have adapted through low metabolism and using up stored food sources. And they frequently find niches that are above freezing — such as the muddy bottom of a lake with ice cover to minimize the impact of temperature drops.
Here’s a description of how water turtles hibernate from the Turtle Puddle website:
“They go deep into the pond and snuggle down into some mud and leaves at the bottom. Their bodies slow down so they don't need to eat anymore.
Their hearts slow down too so that they beat only once every few minutes. They stop breathing through their lungs. Because their bodies are running at such a slow speed, they don't need much oxygen, but they do need some.
They can get the small amount of oxygen they need from the water. It sinks in through specialized skin cells that are just inside the tail opening.”
Pretty amazing stuff.
Just to further complicate things (Mother Nature likes to hedge her bets), there are animals, such as fish, that can’t hibernate, but go dormant.
The study of hibernation falls into the category of physiological and biochemical zoology. It will be interesting to see how animals adapt to climate change and global warming.
Even people who don’t mind the cold dark days of winter, get a chance to think about hibernation every February, when media attention is focused on groundhogs and whether they will come out, and, if so, will they see their shadow.
But you don’t have to wait until then. There are still plenty of non-hibernating animals, such as chipmunks, skunks, and squirrels, out and about on mild winter days or nights — right in our backyard.
Groundhog, a hibernator
Chipmunk, a non-hibernator