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  • Groundhog Hibernation

    Mr. Murray's 7th Grade Students
    Dolphin Senior Public School
    Mississauga, Ontario

    When groundhogs begin hiberation, they are a little more plump than usual. There is 1 to 2 cm of fat underneath the skin and body of a groundhog when they are ready to hibernate. The groundhog lives on that fat during a hibernation which it gained the previous fall. It uses up between 1/3 to 1/2 of that fat.

    Of course groundhogs need a place to sleep, so like their cousins, the prairie dogs, groundhogs live in underground dens or burrows. Groundhogs sometimes have two dens. One for the winter and one for the summer. The summer dens are dug in open fields or clearings. The winter dens are dug in the middle of the woods where it is more protected. The groundhog digs its den in well-drained soil so it will stay dry. Every groundhog begins by digging a tunnel for their den. Then they go on to making a room for hiberation and sometimes a toilet room.

    Groundhogs begin to hibernate about the middle of Septemberin northern areas. In the southern areas of their range in the United States, they may begin hibernation in late October.

    ......Emerging From Hibernation

    The very first thing that a woodchuck's body does in the spring is raise its heart rate up to 80 beats per minute. Then its body, which has been inactive all winter begins shivering to warm itself. Just waking up takes several hours, but of course this is because the woodchuck has been asleep all winter. After this process the sleepy groundhog digs its way out of the burrow. Some woodchucks in certain areas awake and appear earlier than others. Both and captive woodchucks emerge when the days grow warmer (in mid- March.

    According to Dan Stuckey, naturalist at the Kortright Centre for Conservation, (a nature centre operated by the Metro Toronto and Region Conservation Authority) groundhogs typically emerge in mid to late March in Southern Ontario. This would be as late as April in more northern areas.

    Full grown male woodchucks leave their dens the earliest, followed by full grown females, and the younger woodchucks a few weeks later. Once outside, the woodchuck looks a lot difterent from when it first had gone into it's den to hibernate the previous fall.

    After 4-5 months of not eating, the woodchuck has lost one third to one half of it's autumn weight. As you can imagine the woodchuck is very hungry and begins to search for food, but finding food proves to be very hard when the snow still covers the young sprouts in the early spring. The woodchuck may be forced to feed on the bark and twigs of the cherry, sumac, and wild dogwood trees. When green plants begin to grow however, the woodchuck gains it's weight back and gets even heavier.

    The first thing on a male woodchuck's mind after emergence, even before food, is mating. Older male woodchucks waste no time in getting to other female's burrows in the spring. Younger male woodchucks may wander around for days before they mate.