A groundhog and a woodchuck are two common names for the exact same species of North American rodent, Marmota monax. This animal is a large ground squirrel, a member of the marmot genus, and is also known by various regional names like whistle-pig or land-beaver.
Taxonomy and the Origin of Names
The groundhog belongs to the family Sciuridae, which includes squirrels, chipmunks, and marmots. As one of 15 species in the genus Marmota, the groundhog is exceptional because it prefers lowland areas, unlike most other marmots which inhabit mountainous terrain.
The name “woodchuck” is not related to the animal’s ability to “chuck” or throw wood, which is a common misconception. Instead, it is an anglicized version of an Algonquin name, such as wuchak or wejack. Early English settlers adapted this indigenous term, likely influenced by the familiar English words “wood” and “chuck.” The name “groundhog” is a descriptive common name, reflecting the animal’s burrowing habits and stout, pig-like appearance.
Physical Characteristics and Diet
This stout-bodied rodent typically weighs between six and twelve pounds and can reach a body length of up to 20 inches. Its thick coat varies in shades of brown or grizzled gray, often with darker feet and buff underparts. The groundhog possesses short, powerful legs equipped with strong claws, which are adapted for digging.
The groundhog has four large, chisel-like incisors that grow continuously at a rate of approximately one-sixteenth of an inch per week. The animal is primarily herbivorous, consuming up to a pound of vegetation daily, including wild grasses, clover, alfalfa, and dandelions. While their diet is mainly plant-based, they occasionally eat small insects such as grubs or grasshoppers, particularly in the early spring. In the wild, groundhogs typically have a lifespan of two to three years.
The Science of Burrowing and Hibernation
Groundhogs create complex burrow systems that serve as shelter, nurseries, and protection from predators. A typical burrow features a main entrance, often marked by a large mound of soil, and two to five auxiliary entrances for escape. The system can span 15 to 25 feet horizontally and includes a main nesting chamber positioned below the frost line.
The groundhog is one of the few true hibernators among North American mammals, entering a state of torpor from late fall until early spring. The animal must accumulate significant fat reserves, sometimes doubling its summer weight, to survive. During hibernation, its body temperature drops from around 99 degrees Fahrenheit to as low as 37 degrees Fahrenheit. The heart rate slows drastically from approximately 80 beats per minute to just five beats per minute, and breathing may slow to only two breaths per minute.