Rock chucks and woodchucks may have similar names, but they are two different, albeit closely related, species of marmot. Marmots are essentially large ground squirrels, the biggest members of the squirrel family. Rock chuck is a nickname for the yellow-bellied marmot and woodchucks are perhaps better known as groundhogs.
One difference between the two marmots is where they live. The woodchuck lives primarily east of the Rocky Mountains in the United States and north into Canada. It does live in the far northwestern part of Canada as well, extending to southern parts of Alaska. They typically live in forests with low elevations, pastures and even in human suburbs. The rock chuck lives in the western United States and into Canada, from the Sierra Nevada Mountains in the south to Alberta in the north. Rock chucks can live in grassy forested areas like woodchucks, but they also populate deserts and mountains unlike woodchucks.
Woodchucks are usually between 18 and 24 inches long, with a 7- to 10-inch tail. They can get hefty for their size, weighing around 13 pounds. Woodchucks have fur that is light to dark brown in color, and sometimes gray. Their paws are dark brown to black. Yellow-bellied marmots are a little smaller than woodchucks, with an average weight of only 8 pounds, but are similar in overall length. They are paler in color than woodchucks, with overall yellow-brown color and a yellow-orange colored tummy. Pale yellow spots decorate the sides of a rock chuck’s neck and they have white fur between their eyes.
Rock chucks and woodchucks have very different social behavior. Woodchucks are solitary and territorial animals, with males having overlapping territories with females. Rock chucks on the other hand, frequently live in colonies. According to University of Michigan’s Animal Diversity Web, 75 percent of rock chucks live in colonies.
Woodchucks are not as long-lived as their rock chuck cousins. Woodchucks typically only live between four and six years in the wild. Disease and local predators are the most common reasons woodchucks die in the wild. In captivity, they live a little longer, up to 10 years. Rock chucks live much longer in the wild. They can survive between 13 to 15 years old, older than even captive woodchucks.