If science could unlock the secrets of hibernation, we could save a bundle on grocery bills every winter.
We would go into a torpor. Our metabolism would slow down. Breathing and heart rate would drop to one-tenth of normal, and body temperature would fall to the ambient temperature of our room.In this state, living off our bodies' fat reserves, we'd remain in a state of dormancy until the cold of winter turned into the warmth of spring.
How to accomplish this without internally damaging our bodies, however, is one of the mysteries that has puzzled civilization for centuries.
As a graduate student in California, Chairman Bruce Wunder of the zoology department at Colorado State University began studying ways animals adapt to seasonal environments.
His research wasn't on hibernators, however, but on aestivators - critters that while away the summer in underground dens the same as their cold-weather cousins do in winter.
"The antelope ground squirrel in the Mojave Desert goes into torpor from July until March," Wunder said. "This squirrel, weighing about four ounces, aestivates because it's too hot and dry to survive between the seasonal rains."
When the squirrels do come out, it's all work for four months, getting a drink, putting on fat, finding a mate and preparing to return to sleep.
Life's not quite so hectic for hibernators, which have most of the year to prepare for the few nasty months of winter.
The term "hibernate" often surfaces in talk about bears, but there's a spirited debate among biologists whether bears do or don't. Some say bears are "super hibernators;" others that they merely go into a state of "winter lethargy."
In animals whose hibernation isn't disputed - hamsters, dormice, marmots, pocket mice, ground squirrels, bats - normal body temperature falls to a fraction above freezing, Wunder said.
"The ground squirrel's body temperature drops to just above freezing," he said. "Their breathing rate drops to two or three breaths a minute."
True hibernators, Wunder said, are difficult to arouse from torpor because their bodily functions shut down to a point in which it would take up to 90 minutes to warm up enough to regain motor functions.
A bear's temperature, on the other hand, only drops about 10 degrees, and it can come back to speed rather quickly if threatened. "If a bear's temperature dropped to 32 degrees, it would take it 24 hours for it to warm up again," Wunder said.
"We believe the bears don't have to drop their metabolic rate that much because they're so big they can put on enough fat to keep their temperature up and still make it through winter with no trouble at all."
Different circumstances can trigger hibernation, Wunder added. For some ground squirrels, i's simply shorter days - a phenomenon that can be tested under lights in a laboratory.
For others, he said, it's an endogenous rhythm. Kept in total light or total darkness, they go into hibernation within a couple of weeks of when they would in the wild.
It's not clear whether man could hibernate, Wunder said. Since man doesn't do it naturally, the changes that occur in membrane function and various organs might not happen properly.
"On the other hand," Wunder said, "it would be helpful to find the so-called `hibernation triggers.' We're looking at chemicals that are transported in the blood, particularly chemicals found in the brain, that control hibernation.
"There's some data to show you can take certain fractions of blood from hibernating animals, put it in hibernators that aren't in hibernation, and get them to go into torpor.
"If we could refine that, imagine what it could mean for man in prolonged space travel."