Feb. 2, 1998 FORT COLLINS--Whether Punxsutawney Phil chooses six more weeks of winter hibernation on Groundhog Day has more to do with the makeup of fatty acids in his body than being scared by his own shadow.
Colorado State University biology Professor Greg Florant, an international expert on hibernating animals, recently discovered that high amounts of linolenic acid can actually hinder hibernation in marmots, a cousin of the groundhog. Excessive amounts of this long-chain polyunsatured fatty acid also can cause the animals to be more active--even continue to eat--at a time they are supposed to enjoy a long winter's nap.
Florant said that linolenic acid (also called 18:3 and n-3) and linoleic acid (also known as 18:2 and n-6) have been identified in other hibernating animals as key influences on successful hibernation. But Florant's recent work with graduate student Vanessa Hill offers the first evidence that high levels of linolenic acid may inhibit successful hibernation, while balanced combinations of the two acids provide a restful sleep.
"When Punxsutawney Phil is pulled from his burrow on Groundhog Day, it may actually be the ratio of these fatty acids that determine whether he'll come out of hibernation early," Florant said. "Through our research, we now know these fatty acids play a very important role in successful hibernation, particularly if high levels of linolenic acid are present."
In the spring and summer, hibernating animals like marmots and groundhogs prepare themselves for the winter by gorging themselves with leafy plants, seeds and nuts that contain varying amounts of these fatty acids. The seasonal drop to colder temperatures in September and October trigger a series of physiological events that cause the animals to begin hibernating.
The most important catalyst for hibernation is a slow decrease in the animals' body temperature from about 37 degrees to 5 degrees. With their bodies nearly frozen in this state, metabolic and other bodily functions slow dramatically, leaving the animal immobile.
Mysteriously, the animals' body temperature slowly warms back to normal levels about every 7 to 10 days during hibernation, allowing them to waken for short periods of time. After this short waking period, their body temperatures begin to mysteriously drop far below normal and they enter the hibernation state once again.
"This is an amazing process because it requires a great deal of energy. They fast for seven months, relying solely on the fat they've stored as an energy source," Florant said.
To study hibernating animals, Florant uses a special chamber at Colorado State that mimics conditions the animals would experience in the wild. The chamber is dark and cold--about 5 degrees--and is equipped with red lights, which the animals cannot see. Currently, about 20 marmots and a dozen ground squirrels are spending the winter in Florant's hibernation chamber, unaware of their involvement in the biology professor's research project.
So what do the hibernating marmots in Florant's lab predict for Groundhog Day?
"These guys never see their shadow, so it's going to be a long winter," he said.
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