|8/27/2013 1:35:00 PM|
Sleeping it off
I enjoy sleeping late in winter.
|A young Dean Anderson and hibernating Townsend’s big-eared bats. photo by Jim Anderson|
|Townsend’s ground squirrel. photo by Jim Anderson|
I wonder if I took to hibernating (I have plenty of fat reserve to do so), if my tired old brain would improve. At 85 it seems to be going downhill rapidly, and inasmuch as shoveling snow and shivering through a Sisters Country winter is no longer fun, maybe I could achieve three goals at once by hibernating: Stay warm all winter; not care about snow piling up, and improve my brain.
The classic hibernators in Sisters Country are resident bats, ground squirrels (AKA sage rats) and marmots (AKA rock chucks) - along with mourning cloak and California sisters butterflies, and other smaller creatures too numerous to mention. The sage rats and marmots, incidentally, have already gone down; they don't sit around waiting for it to get cold.
Arctic ground squirrel hibernation tactics call for them to shiver themselves awake from time-to-time in winter to keep their brain from dying. Our Townsend's long-eared bats do something very similar.
Back in the '70s, when I was banding bats to try and find one or two I'd recognize in summer zooming around the high country lakes and streams so I'd learn more about their distribution and hibernation, I discovered they, too, wake up during hibernation and move around.
There's a little-known lava cave I discovered near Bend that may still be a safe place for 30 or 40 Townsend's big-eared bats to spend winter. When I accidently walked into it there were about 60 of our rare big-eared bats sleeping away winter, and I had the pleasure of banding most of them without waking them.
When I went back into the cave a week later to check them, lo-and-behold they had moved to different locations in the cave, and I thought it was my fault. Two weeks later I returned to see if they were doing OK, and they had moved again. I had wiped my footprints from the sandy floor when I left, and no one had been in the cave after, so I was curious about was going on.
I built a series of numbered wooden markers and placed them under 10 of the sleeping bats and sure enough, when I returned, I found the bats had moved again. I was associating with the brainy biologists at the primate research center in Beaverton in those days, so I took myself off to The Swamp to have a discussion with them about mammalian physiology during hibernation.
I discovered that bats, during hibernation, allow themselves to go so deep into their winter stupor they are close to dying from oxygen starvation. Plus, the females arrest the development of their embryo until spring, when they again are feasting on nocturnal insects and have the nutrients to keep the pups growing healthily.
It seems when the oxygen content in the bat's blood drops to a critical level, and death is imminent, a chemical is developed in the blood that stimulates the brain and shouts, "Wake up - you're dying!" Eyes open and the bat drops from the ceiling of the hibernaculum and begins flying around, breathing deeply, pumping oxygen into its blood to get the muscles going. Then it hangs itself (literally) by it's toenails on the ceiling and goes back to sleep for another couple of weeks.
It can't be overdone, however; they have just enough fat reserves - from the myriad insects they devoured all summer - to make it through winter and that's it.
Now I wonder if our ground squirrels and marmots also do what bats and Arctic ground squirrels do in winter. Perhaps a couple of our brainy Sisters High School students from Rima Givot's biology class will start texting each other to come up with a method to supply that information.
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