Late spring in Alaska and marmots are emerging from their winter hibernation. For the past six to eight months, marmots have been sleeping in winter burrows with their body temperature lowered and all bodily functions, like breathing and heartbeat, greatly reduced.
Marmots are big ground squirrels, and they're social animals. A marmot family has its own burrow, but the burrows are located near each other, forming a colony. Alaska is home to three kinds of marmot - hoary marmots, Alaska marmots, and woodchucks. Woodchucks are known as groundhogs in the Eastern U.S. The name woodchuck originated as a Cree Indian word and does not describe the animals' habitat preference or behavior.
Woodchucks and hoary marmot hibernate alone, in the same burrow where they spend the summer. To protect themselves from the cold, woodchucks and hoary marmots plug the tunnel between the outside world and their nest chamber. They emerge in April or early May to find food and mates.
Alaska marmots, in contrast, are adapted to the harsher winter climate of northern Alaska. They hibernate as a group in a special winter den which has a single entrance and is characteristically located on an exposed ridge that becomes snow-free in early spring. The entrance is plugged after all colony members are inside, and no animals can leave until the plug thaws in early May. Consequently, Alaska marmots mate before they emerge from their winter den. These dens are relatively permanent for each colony, and may be used for many winters.