Common predators for groundhogs include wovles,coyotes,foxes,bears and dogs. Young groundhogs are often at risk for predation by snakes which easily enter the burrow.
Groundhogs primarily eat wild grasses and other vegetation, including berries and agricultural crops, when available. Groundhogs also eat grubs,grasshoppers, insects, snails and other small animals.
Groundhogs are one of the few species that enter into true hibernation, and often build a separate "winter burrow" for this purpose. This burrow is usually in a wooded or brushy area and is dug below the frost line and remains at a stable temperature well above freezing during the winter months. In most areas, groundhogs hibernate from October to March or April, but in more temperate areas, they may hibernate as little as 3 months. To survive the winter, they are at their maximum weight shortly before entering hibernation. They emerge from hibernation with some remaining body fat to live on until the warmer spring weather produces abundant plant materials for food.
Groundhog hibernation gave rise to the popular American custom of Groundhog Day, held on the second of February every year. Tradition dictates that if a groundhog sees its shadow that day, there will be six more weeks of winter, though such a prediction seems a sure bet over much of the groundhog's North American range. In the spring, females welcome a litter of perhaps a half dozen newborns, which stay with their mother for several months.
