What is a Rock Chuck?
Yellow Bellied Marmot
A rock chuck, or yellow bellied marmot, is a ground squirrel common in the Rocky Mountains. It is related to wood chucks, or ground hogs, whose habitat is in eastern North America. They are approximately the size of a cat, about 50 centimetres long, with a tail 15 centimetres in length. They are named for the yellowish fur on their bellies, and usually live 13 to 15 years.
Yellow bellied marmots live in colonies in burrows which they dig in open territory at higher altitudes, usually above 2000 metres above sea level. They prefer to dig the entrances to the burrows under rocks scattered on grasslands, meadows, or scattered forest, where the rocks protect them from predators, such as owls, eagles, badgers, wolverines and coyotes. The burrows typically have several entrances, so the rodents can escape strategically if one of the entrances is unsafe.
Yellow Bellied Marmots are common in McArthur Park, Kamloops, where tourists and residents enjoy watching the colonies that sun and play near the path
Rock chucks eat a varied diet of whatever they can forage close to the ground, consuming fruit, flowers, leaves, seeds and sometimes insects. They are active during the day, and are especially active in gathering food in early morning and evening, resting in their burrows during the heat of the day.
Ground Squirrel Hibernation
Like other ground squirrels, yellow bellied marmots hibernate in winter. They prepare deeper hibernation burrows, up to five meters deep, so the resting chamber is below the frost line and the hibernating animals stay warmer. Depending on the snowfall and temperatures of their locale, they hibernate from late September or October until April or May. At the end of the summer season their diet includes high-protein seeds as much as they can find, to build up a layer of body fat to support their metabolism during their winter sleep.
Once they emerge from their burrows in the spring, rock chucks mate, and the young ones are born in May or June after one month gestation, in nests of grass the parents have built inside the burrows. Like other mammals, the young, usually born in litters of 3 to 5 pups, drink milk from their mother. For the first three weeks the babies stay underground. Usually around two weeks after the mother moves them above ground, she weans them so they can have several months to build up fat to help them survive their first winter's hibernation, when they will lose up to half of their body weight. Many yearlings do not survive their first winter.
Yellow bellied marmots live in family groups with one adult male and two or three females, who take care of all the young collaboratively. Living in groups is a survival measure, and often one will be seen guarding while the others feed, groom, play or rest. In the second summer, the juvenile males and some of the females are driven away to form their own group, whereas some of the juvenile females may stay with the mother for their lifetime. Once the pack gets too large, it splits and a young male takes over one of the groups of females.
Although yellow bellied marmots look cute as cats, they are wild animals and should not be petted. They may be carriers of disease, such as rabies, or the plague caused by the bacterium Y. pestis.