The Seven Sleepers


(This Buffalo News column was first published on January 31, 1994.)


      Groundhog Day, that folklore favorite now co-opted by the entrepreneurs of a small Pennsylvania village of complex orthography, will occur again this Wednesday. Punxsatawney Phil will be rudely nudged out of deep slumber to emerge from his den and predict the remaining tenure of this winter.


      I for one hope that he opts for more winter. We don't need the flood that rapid melting of all this snowmass might create.


      The groundhog or woodchuck is only one of the mammals known as "The Seven Sleepers", the familiar animals that spend all or much of the winter in the arms of Orpheus. (Allen Benton of Fredonia first called my attention to this designation and much of what follows is based on his information.)


      The seven are little brown bat, bear, chipmunk, jumping mouse, raccoon, skunk, and of course woodchuck. When you look at that list carefully, you soon realize that it represents a wide range of animals. Three different taxonomic orders are represented: bats, carnivores (bear, raccoon, and skunk), and rodents (chipmunk, jumping mouse, and woodchuck). And only two of the seven sleepers come from the same family: chipmunks and woodchucks are grouped among the squirrels.


      Lengthy winter sleep then certainly represents convergent evolution, that is a similar adaptation by widely differing species. They all do indeed have the same problem: how to make it through the winter months faced with the reduced amount of available food to provide their body warmth, the low temperatures that drain what little warmth they do have, and the deep snows that make getting around so difficult and that further deplete their energy.


      When you think about it, hibernation, if you can pull it off, is a wonderful response to winter. You simply batten things down, just as you do your summer cottage, and wait for better times. I suspect that by now some of us wish that we had such an alternative to cabin fever. It is a response so attractive in fact that it is at least theoretically considered as a human answer to the life-span times of space travel and to our present lack of cures for deadly diseases. For now though, those who seek to translate science fiction into science fact have these sleepers to lead the way.


      There is quite a bit of variation among the seven sleepers. The only true hibernators, the ones that sleep all winter, are the woodchuck, the jumping mouse, and the little brown bat. Even here there is an exception: some male groundhogs awaken and venture out at about this time to seek the den of a female, with whom they will cuddle for the remaining weeks of cold. Otherwise these animals lie -- or in the case of the bats, hang -- in deep torpor, their temperature near that of the air around them, their pulses a few beats a minute, their bodies stiff.


      Disturbing these hibernators, especially the bats, can condemn them to death, for it takes much energy to raise their body temperatures to react and once they are active there is no available food to replace that lost energy. Thus it is especially important for spelunkers to avoid bat caves like the ones in Wyoming County during winter.


      In decreasing order of dormancy, the others are: bear, chipmunk, raccoon, and skunk. Bears sleep for long periods, but females give birth in winter and successfully -- if groggily -- nurse their young. Chipmunks are deep sleepers, but they wake often to snack on hoarded food. Raccoons and skunks even venture out on mild nights in search of a meal.


      But you can bet that they all slept through the weather of the last several weeks.-- Gerry Rising