Where Does The Pesky Woodchuck Go?

That pesky woodchuck ( Marmota monax) is hibernating. Yes it’s true, and they are amazingly designed to do so. There are only three true hibernating mammals in the North East. The brown bat, the jumping mouse, and the woodchuck. Other mammals that you may not see and who often disappear during the colder months, like bear, skunk, or raccoons, are actually considered deep sleepers, not true hibernators. These animals do become inactive for part of the winter, but their body temperature remains higher than the surrounding air temperature, and they may stir occasionally to venture out during a warm spell. A true hibernator stays hibernating for the long haul. Knowing what I do about the woodchuck’s ability to hibernate, allows me some sympathy during the summer when he’s out munching our beans or enjoying the neat rows of greens in my garden. During the summer he is eating almost constantly to store fat for the winter. He will live on this fat for the entire time he spends underground in his burrow of grass and leaves, where he’ll curl into a tight ball ( less surface area) and remain for the next 5 months or so. Woodchucks generally go into hibernation from November to early April. At this point they are able to reduce their breathing rate and body temperature to extremely low levels. A hibernating woodchuck takes a breath about every six minutes. They are able to lower and maintain a body temperature of about 38 degrees, their normal body temperature being closer to 96.8. Its heartbeat will drop from its normal 80 beats per minute to about 4 beats per minute. During their time in hibernation they will lose about 47% of their body weight. They live the entire time absorbing stored body fat. There is really no fecal matter during hibernation because there is nothing moving through their digestive tract. Woodchucks, during hibernation, have an increase in brown fat deposits. This brown fat is usually found around an animals vital organs and along its back and shoulders. Brown fat has a higher rate of oxygen consumption and heat production than white fat. It’s the kind of fat you want to burn when sleeping through the winter. Considering the energy that it takes for a woodchuck to endure and survive a long Maine winter, I should be growing a row or two in my garden just for him. Fortunately, we have not had woodchucks in the gardens for a long, long time. Two patrolling dogs probably have something to do with this.
Years ago I spent a couple of winters teaching a winter ecology program in Vermont. I became fascinated with how plants and animals adapt to a cold climate. Understanding just how difficult it can be for plants and animals to acclimate to extreme winter temperatures, makes the arrival of spring and warmth even more of a celebration. We’ve had really cold temperatures lately, the woodstoves are eating up wood, and being outdoors means lots of layers. I think of the animals and plants who all have their unique ways of tolerating and surviving the cold. Amazing, really.