Winter World_ The Ingenuity of Animal Survival - Bernd Heinrich [106]
Hibernating bears accomplish metabolic feats that, if we knew their secrets, would likely lead to cures for many human ills. They have the secrets of how to survive lack of exercise, and then, after five months of resting, of how to get up and walk up a mountain. In all of those months of what amounts to bed rest, they suffer no bed sores. They have marginal loss of muscle mass and no change in muscle fiber type. Despite their non-weight-bearing position for months at a time, they do not suffer from bone loss or osteoporosis. After burning fat for fuel for months during which their cholesterol levels become double those of humans and those they have in the summer, yet they still don’t suffer from hardening of the arteries or gallstones, conditions resulting from high cholesterol levels in us. Most of the enigmas that have been revealed in hibernating bears have not been solved, maybe because bears just can’t be studied as conveniently as lab rats. We can be reasonably certain, however, that once we understand how bears hibernate through the winter, we will also have a larger window into ourselves. We inadvertently simulate a hibernation-like state of inactivity in our modern environment, a new state of nature to which we are not well adapted.
22
STORING FOOD
The vegetation in northern New England is at its lush green peak by mid-August. Yet, the azure blue butterflies have not been around since mid-May, and the tiger swallowtails since mid-June. Each species appears and dies in its specific time slot. The pupae of most insects have by now been arrested in their development for a month or two, and they won’t revive from hibernation to develop into adults until their specific times next spring or summer. Meanwhile, the monarchs have finally arrived from the south, and some of their fast-growing caterpillars are already developing into pupae that a week later turn into adults that will begin their journey back to the south when their food, the milkweed plants, begin to dry up. Ants are still tending the aphids that they milk for their honeydew, but soon they will begin to bring them to safe underground quarters for the winter. Bears and woodchucks are fattening themselves up. Cicadas call shrilly during the day and the constant chirping of crickets, grasshoppers, and katydids continues night and day. But in two more months these songsters will be stone-cold dead, perhaps even before the first fall frosts. There are signs all around of profound change about to happen, as the necessary physiological and behavioral adjustments for the coming winter are being made. In chipmunks, certain birds, honeybees, and us, the most important preparation for winter is storage of food.
In our garden the apples, pumpkins, and squash are still ripening, but the onions, garlic, carrots, potatoes, and string beans are ready for harvest. We’re starting to freeze, can, and dry the bounty for winter, and I’ve been sawing wood and stacking it in the cellar. The farmers’ barns have long since been full of hay to tide the cows over through May, and the unmowed fields and orchards are ablaze with the yellow bloom of goldenrod and the blue New England asters that are abuzz with honeybees topping off their own fuel depots in their hives.
For my family these rituals of food and wood storage fulfill some basic urge, but they are certainly not obligatory, thanks to our twenty-first-century transportation and monetary systems. However, just one hundred years ago, the work of food gathering and storage was a necessity for survival for those who did not rely solely on hunting.
Among mammals, food hoarding can be an alternative to hibernating or migrating, but only a small percentage of the total number of species on the planet store food. And while we may be able to do it on the grandest scale, humans are by no means the most spectacular of food hoarders. In late summer, the pikas (Ochotona