Chipmunks in the backyard have decided that winter is over, and it’s time to come out of hibernation and do some spring cleaning. This little guy sat in a bush by one of the bird feeders, grooming itself, basking, and generally looking a little groggy from all that sleeping.
Unlike other hibernators (woodchucks, ground squirrels, even bears), chipmunks don’t lay on a big surplus of fat before entering hibernation in the fall. Instead they arouse every couple of weeks, eat a little of the nuts, seeds, fruit, etc they have cached in their burrow, and then go back into a torpid state where their body temperature is about the same as that of their burrow.
NASA scientists have been fascinated by the special physiology that allows hibernators to lower their core body temperature almost to freezing and still recover organ function after rewarming. Although adult humans can become incapacitated with as little as a 3.5 degree drop in core temperature, some young children can recover from severe hypothermia (more than a 10 degree drop) following drowning in extremely cold water without loss of function. Perhaps we do have some physiological ability to withstand a core temperature drop, but have simply lost it as adults.
Will our great-grandchildren be doing this to cross galactic distances?