Groundhogs are mainly herbivores, meaning they eat primarily plants. Their diet consists of a variety of plants and plant material, including grass, fruit and bark, and they often prove a nuisance to farmers and gardeners when they help themselves to crops. Occasionally, groundhogs may eat insects or other animal matter.
Groundhogs eat incessantly during the summertime in order to prepare for hibernation in winter. The extra feeding provides them with a reserve of fat that functions as a energy source during hibernation. In order to facilitate energy conservation, groundhogs have a slower heart rate and lower body temperature while they hibernate.