The groundhog (Marmota monax), also known as the woodchuck or whistlepig, is a solitary species of marmot native to Eastern North America. These animals have no problem living right around humans, and you might see that one has dug a burrow and moved right into your own backyard. Groundhogs are pretty common animals. In the wild, they can live up to six years. In captivity, groundhogs reportedly live up to 14 years.
Groundhogs are great diggers. Their upper body is pretty strong, and has to be, for digging those amazing burrow systems they're known for making. The claws on the front paws are sharp and good for digging. When the front feet dig, the hind feet push out the loose dirt. The burrow is usually dug under a pile of rocks or tree roots. There's a drop down right after the entrance, then a long tunnel that opens up to a chamber. There can also be a special hibernation chamber, and other escape entrances and exits. A single groundhog does all that digging itself in just a couple days. Because groundhogs are the best diggers in North America and dig so many holes, they get holes started for most animals that live in burrows.
A groundhog spends about seven hours a day eating. Groundhogs are primarily vegetarians, they eat lots of different plants, including berries and agricultural crops, when available. In early spring, dandelion and colts foot are important groundhog food items. Some additional foods include sheep sorrel, timothy-grass, buttercup, tear thumb, acrimony, red and black raspberries, mulberries, buckwheat, plantain, wild lettuce, all varieties of clover, and alfalfa. Occasionally, they eat insects and worms. But they mostly eat grass. Groundhogs eat so much grass each day; enough to fill up a sink. A groundhog's body is designed to be low to the ground so they can eat as much grass as possible as fast as possible. One of the groundhog's powers is ever-growing teeth. Groundhog teeth grow continuously, and the groundhog has to keep grazing and chewing to to wear those teeth down.
With their heads down in the grass, a groundhog can be vulnerable to predators. A lot of animals love to eat groundhogs, including wolves, grizzly bears, golden eagles, coyotes, American badgers, great horned owls, bobcats and red foxes. American goshawks will eat young groundhogs. Good thing groundhogs are always a a quick sprint away from a burrow. In fact, a groundhog rarely eats grass more than ten feet from its burrow, so whenever it senses a predator, it can quickly escape to the safety of its burrow.
For groundhogs especially in the north, summer is the time to get as fat as they can. Because when summer's over, all of the groundhog's food disappears. There's no fresh grass. Without fresh grass and vegetation, there is nothing to eat, so how does a creature who depends on eating fresh vegetation survive? With all that extra weight gained during the summer, a groundhog enters its burrow, and goes into a super sleep called hibernation. Before they hibernate, groundhogs wall themselves in to protect themselves from predators while they're sleeping and defenseless. Their body slows way down to save energy. Their heartbeat slows to only four beats per minute. They breathe out, and then don't breathe in again until six minutes later. They get colder, their body temperature dropping until their almost as cold as ice. This is true hibernation. Groundhogs slow their whole body down so it doesn't have to use much energy. All the energy they needs is stored in the layer of fat they put on in summer when they stuffed themselves with much grass as they could. That fat is all they need to survive through the winter when there is no grass to eat. When spring finally comes, they emerge from their burrows and start eating grass again.
They are very famous for their own holiday. Groundhog day is every year, February 2nd, but has lots of superstition and controversy. Many people think that when a groundhog wakes up from hibernation and sees its shadow when it exits its den, it'll mean six more weeks of winter. If they don't see their shadow, spring will be on its way. The truth is that male groundhogs aren't checking the weather or watching for shadows. They come out of their burrows to check out female groundhogs hibernating in their territory and usually go into female groundhog burrows to mate with them. Groundhogs have to have their babies early in the spring, just as the grass is growing so they can eat as much grass as possible, and put on all that extra weight that they need for hibernation in the next winter.
Surprisingly, groundhogs are faster than they look and can run as fast as an average human. They also can climb (but very clumsily) and can even swim for short distances. Unlike other marmot species, groundhogs are solitary and can be very territorial.