Hibernators Week: Vancouver Island Marmot (Marmota vancouverensis)
It’s the middle of winter, and although I can take naps, I can’t do what I’d really enjoy, which is hibernate. The next best thing is to celebrate hibernation, torpor, and estivation of other mammals. And let’s start by clearing those up, in case, like me, you didn’t know the differences between them. Here we go:
- Hibernation, torpor, and estivation are three types of dormancy that animals experience. (There’s one more, diapause, but it doesn’t really apply to mammals, so forget it for now, unless you just can’t, in which case, go ahead and click on the link to Wikipedia.) Dormancy is a state of suspension or slowing of normal physical functions.
- “True” hibernation is an extreme form of dormancy. It generally takes place in the winter and usually involves curling up in a den of some kind, lowering your body temperature, and slowing your heartbeat until it can barely be detected. Only smallish mammals are true hibernators. (If you know French, you will recognize the similarity between the French word for winter—hiver—and the word hibernate.)
- Torpor is less extreme. Your metabolism and heart rate slow, but not as dramatically as in hibernation. You can wake up from torpor if you have to without too much trouble, but you will probably stumble around a bit before you shake it off.
- Estivation was completely new to me, but it’s neat. It’s like hibernation, but it happens in hot and/or dry times and places: it’s sort of a summer version of hibernation (and in Italian, estivo or estiva indicates that something is occurring in the summer).
This week, I’ll be drawing and writing about animals that practice all three of these kinds of dormancies (I think…), so I’ll be using the word “hibernator” not in its pure sense but to mean torpor or dormancy. Okay? Okay.
Now. Our marmot here is a true hibernator. In the winter, marmots’ hearts beat only three or four times a minute! Three…or…four…times…a…minute. So slowly. This species hibernates in its burrows from October to May. So right now, Vancouver Island marmots are snoring sweetly underground, snug as can be.
All 150 of them.
Seriously. This guy is one of the most endangered mammals in the world. Confined to just a few mountain areas of their Canadian island—and nowhere else in the world—the marmots have been victim not just to deforestation directly, but also to the effects deforestation has to the balance of the Vancouver Island ecosystem in general. It seems complex, but basically, the logging industry makes some areas more appealing to marmots than they should be, and they turn out to be very ill-suited to hibernation. And the logging destroys other animals’ habitats, meaning the predator/prey relationships on the island are screwy, and now the marmot is more vulnerable than usual to its natural predators.
Like other marmots, the Vancouver Island variety has a sophisticated communication system consisting of a number of different kinds of calls. (The Mammalian Species account of the marmots says that their whistles have three harmonics, a variety of durations, and changing intensities.) You can hear some of their calls at this page from UCLA. (Your dog may take an interest, too.)
The 2010 Winter Olympics will be in Vancouver, and the games have a better-than-usual set of mascots, including a Vancouver Island marmot “mascot sidekick” named Mukmuk.
The Marmot Recovery Foundation is working to save the Vancouver Island marmots from extinction. The group operates a captive breeding and reintroduction program that is showing some success. Its website has some other information and photographs of the marmots, too.