The woodchuck, scientifically known as Marmota monax, is a surprisingly large rodent often recognized as the groundhog. This stout mammal is the biggest member of the squirrel family, Sciuridae, in most of its North American range. Its size often catches observers off guard, prompting questions about its true dimensions. Understanding the woodchuck’s size requires looking closely at its typical body measurements and the significant seasonal changes it undergoes.
Defining the Average Adult Size
A healthy adult woodchuck possesses a stout body structure designed for burrowing. The typical total length for an adult, measured from the nose to the tip of its short, bushy tail, generally falls between 16 and 27 inches. The tail usually ranges from four to six inches. Woodchucks are low-slung animals with short, powerful legs, giving them a broad profile.
The weight of an adult woodchuck varies depending on the time of year, but a standard, non-hibernating animal typically weighs between six and twelve pounds. The lower end, around four pounds, often represents an animal emerging from hibernation or a younger woodchuck. Males tend to be slightly larger and heavier than females. Exceptional individuals preparing for winter can reach maximum weights of up to 14 pounds.
The Impact of Season on Weight
The woodchuck’s body weight fluctuates dramatically throughout the year because it is a true hibernator. During the late summer and early fall, the animal enters a period of hyperphagia, characterized by excessive eating to rapidly accumulate fat reserves. This intense foraging builds the necessary energy stores to survive the long winter months without food.
The accumulation of this fat is necessary because woodchucks do not cache food in their burrows for winter consumption. By the time they enter their winter dens in the fall, their body mass is at its absolute peak. This pre-hibernation weight can be significantly higher than their spring weight, representing their largest size of the year.
During hibernation, the woodchuck’s metabolic rate slows drastically, with its heart rate and body temperature dropping to near-freezing levels. The animal subsists entirely on its stored body fat, which is slowly metabolized to maintain basic life functions. When emerging in the spring, the woodchuck has lost a significant portion of its mass, typically between 30 and 40 percent of its total body weight.
Contextualizing Size Against Related Rodents
The woodchuck is a species of marmot, belonging to the genus Marmota. Compared to common tree squirrels, like the gray or fox squirrel, the woodchuck is immensely larger and stockier, possessing a much wider body and shorter tail. This substantial difference in mass highlights its classification as a giant ground squirrel.
The woodchuck (Marmota monax) is a lowland species, unlike its close relatives. Other marmots, such as the Yellow-bellied Marmot and the Hoary Marmot, generally inhabit high-altitude, rocky, and mountainous environments. The Yellow-bellied Marmot is typically smaller than the woodchuck, usually weighing around eight pounds. The Hoary Marmot, found in western North America, is often considered the largest marmot, potentially surpassing the woodchuck in maximum size.