Key Differences Groundhogs are larger than gophers and have stronger forepaws and bodies. They're avid swimmers; gophers aren't exactly water-bound and sometimes drowning and flooding their tunnels is used as a means of exterminating them, unfortunately and very inhumanely. Groundhogs measure about fifteen to twenty-five inches in length and weigh between four and nine pounds, but can, if they live long enough, grow to be as heavy as thirty pounds. Gophers (pocket gophers, the "true" gophers, called this because of the food-storage pouches in their cheeks) are smaller and measure anywhere from four to twelve inches in length, and weigh as little as three centigrams (three-hundred grams or so) or as much as two pounds and change (about a kilogram). Groundhogs hibernate; gophers don't. Groundhogs swim; gophers don't (at least not very well). Groundhogs breed in their second year, having only one litter per year; gophers breed in their first year and can have two litters per year. Both give birth to relatively blind and helpless young. Do not attempt to make pets of either of these animals unless you are an experienced handler of wildlife or have done PLENTY of research! They can be very sweet pets, but the last thing you want to do is kill one in captivity because of your own negligence or innocent ignorance. Groundhogs are more aggressive than gophers; gophers are quite docile and more easily tamed; either can be raised in captivity in the proper environment and with proper feeding. Even groundhogs can be tamed, but their aggressive nature can be problematic and you have to work hard with them to make them sweet and cuddly. The groundhog has a national holiday named after it; sadly, the sweet little gopher doesn't. (Gophers are very beneficial in gardens and eat weeds in addition to our prized roots and bulbs; given the chance, they can do more good than harm, but if you plant only desired items and eliminate all weeds, gophers have nothing to eat but what you give them, which makes them your competitor rather than your helper. They like dandelions and most tubers and bulbs.) Groundhogs don't have many natural predators due to their size; gophers have quite a long list of natural predators: cats, dogs, coyotes, snakes, raptors (owls, hawks, etc.,) weasels, badgers, and skunks. Groundhogs stand upright outside their burrows and warn one another of danger. It's common to see them foraging or alert outside their homes. Gophers are not as bold. What's a Groundhog, Exactly? The groundhog, also known as the woodchuck (or land-beaver, or whistlepig) is a large rodent belonging to the same marmot family as ground squirrels. Groundhogs are lowland (rather than mountainous) creatures, common in North America and in the northeast- and central-US. They're also found in Alaska, with their habitat extending into southeast to Alabama. They can live up to six years in the wild, but one kept as a pet lived to be twenty-two years old (according to an article at www.wikipedia.org). Reference: http://en.wikipedia.org/wiki/Woodchuck What's a Gopher, Exactly? Gophers are burrowing rodents in the Geomyidae family. Several kinds of ground squirrels of the Sciuridae family are called gophers but are not "true" gophers. There are so many different kinds of gophers, it's best if you read up on them here: http://en.wikipedia.org/wiki/Pocket_gopher. Check out the links at the bottom and they'll tell you all you need to know about a large variety of this cute little species.