Deep in the wild, frozen woodlands of Michigan’s Upper Peninsula, it seems that even the scientists are a different, heartier breed of human. A few years ago, Seth Donahue, an associate professor in biomedical engineering at Michigan Technological University in Houghton, MI, decided to gather a few of his bravest grad students and sneak into caves occupied by hibernating black bears.
Yes, those kinds of black bears. The ones with all the fur … and claws … and teeth.
But these bears also have something else that Donahue was curious about—something that makes the risks associated with rousing a sleeping bear worth it. He wondered how bears could go to sleep for 4-6 months every year and not suffer any bone loss, given that humans who are immobilized by age or infirmity begin to lose bone after only a few weeks. You won’t see a hibernating bear wake up in the springtime with osteoporosis. So … very quietly … very carefully, Donahue and his team took blood samples to find out why the bears’ bones remained so strong despite their long periods of inactivity.
The secret, it turns out, is parathyroid hormone (PTH), a molecule that helps regulate the body’s calcium stores. Humans have it too, but the bear version differs from humans’ in the number of amino acids, which scientists speculate is one reason bear bones are superior. The next step was to figure out how to bottle that stuff up and make it helpful to an aging human population, with aging aching backs.
And here’s where a bear hunter steps into our story. Well, a bear hunter who also has a
