Eye on Nature

Hibernation Bears Explaining

by Jane Kirkland

Nature is seasonal and so am I. As the October days get shorter, I eat more. I don’t even bother to wait for the holiday treats; I just find I’m hungry all the time.

Perhaps I was a bear in a previous life. As far as I’m concerned, bears know how to spend the winter — all snuggled up in a nice warm, dark den. Free of the cares of work, ringing telephones, kids crying, and from the endless trips to schools, ball fields, and grocery stores. As far as I can see, the only problem with hibernating like a bear is that, well, bears don’t hibernate.

Torpor Isn’t Hibernation
Bears spend their winter in a state of inactivity called “torpor.” They sleep much of the winter but they awaken often. Heck, I do that year round! If I wanted to hibernate I’d have to act more like a chipmunk, or a brown bat, or a groundhog. They are the true hibernators — sleeping away the cold months, their bodies slowed down to a near-death state, living off their body fat — and not waking up until it is time. Now that’s the way to spend the winter!

The real difference between these two states of dormancy is body temperature. During hibernation, the body temperature is reduced greatly. In a state of torpor, the body temperature and metabolism rate are reduced only slightly. Some animals undergo torpor on a daily basis as opposed to a seasonal basis. Just remember, that hibernating bear can hear you if you get too close! Torpor and hibernation, both forms of dormant states are adaptations—methods for survival.

So why do some animals like chipmunks, hibernate while others, like deer, stay active all winter? It’s all about survival. Some scientists believe the change in temperature is the biggest drive for states of dormancy. Others say it’s the reduction in or lack of food or water. I can’t help but wonder if size plays a part in dormancy. One would think that smaller animals wouldn’t do as well during periods of drastic climate changes.

Dormancy sounds great and I do my best over winter to practice it to perfection. But it’s not the only way that animals survive winters in the Delaware Valley. Some leave by migrating to the south. And when it comes to migration, temperature isn’t the main factor, food definitely is. Think of it this way — where are the nectar sources and insects in the winter? Migration is a survival adaptation.

A Chance to Take Notice
So what does this all have to do with you and your kids? Winter is an opportunity for you to help your kids take notice of the changes in their environment by watching nature as they wait for the school bus, or as they gaze out the kitchen window during breakfast.

It’s just as interesting to notice the things they aren’t seeing as the things they do. Such a discussion with your children at the dinner table can become a veritable Norman Rockwell painting. Can’t you just picture it? You and the children engaged in a lively conversation about wildlife and nature.

Your youngest surprises you by noticing he doesn’t see any chipmunks or bats or skunks or groundhogs. You surprise the children by explaining that bears really don’t hibernate — they go into a state of torpor. Heck, the kids will think you’ve been watching Animal Planet!

Then, just as you get to the good part where you’re about to explain the differences between torpor and hibernation, you hear the cold rain whipping as the leaves stick to the kitchen window. And you notice just how dark it is at 5:30pm and that you can barely even see the nearby field, where just last summer you saw a mother deer and her fawn.

An empty quietness falls over the table, you notice the absence of birds singing and a chill runs over you as you long for the warmth of a long summer day. And you think to yourself, “Hmmm, maybe we need to adapt to survive.” Of course, hibernation is not an option but there’s always migration. Florida, anyone?

Jane Kirkland of Downingtown, PA is the author of Take A Walk Books, a series of award-winning nature
discovery books for ages 8 and older. She is featured this month on Animal Planet’s newest TV show, Backyard Habitat. For more information, visit www.takeawalk.com