Groundhogs are interesting animals with big personalities. They like to hang out in their field close to home or along the side of roads where they munch on lunch and keep a watchful eye out for lurking dangers.
Fun Facts about Grumbling Groundhogs
Groundhogs (Marmota monax), also known as woodchucks, whistle-pigs and land-beavers, are one of 14 species of marmots. They are rodents belonging to the large group of mammals Rodentia which includes squirrels.
Most marmots are gregarious, but groundhogs are loners. (‘monax‘ means solitary.)
Groundhogs are found only in North America. They prefer to live in open areas such as fields, clearings, open forests, and rocky slopes. They generally dig their burrows in areas where short plants grow, avoiding damp or swampy areas.
Adult groundhogs are territorial among their own species.
Groundhogs can reach 61 cm in length. They weigh around 6 kg but can be much heavier especially in the fall. Their tails grow up to 25 cm long and they live 3 to 6 years. In the warmer months, a groundhog’s incisors grow about 1.6 millimeters each week!
Fur colour ranges from yellowish to dark reddish brown. An intermediate brown colour is the most common shade. The fur is usually grizzled in appearance because of light-coloured tips on the hairs. The fur on their belly is straw-coloured and their feet are black.
Groundhogs are diurnal (active during the day).
Groundhogs are voracious eaters. Their day consists of eating, sunning themselves, digging and eating some more.
They are herbivores and therefore enjoy mostly wild grasses as well as some nuts, bark, berries, and vegetables. They occasionally eat insects, birds’ eggs and other small animals. Adults will eat more than 0.5 kg of vegetation a day.
These brown, furry rodents may seem cute and cuddly, but they do not make good pets. In addition to the fact that keeping them is illegal, groundhogs like to chew on everything! They like to hide is places from which you will have difficultly extracting them. They are excellent climbers, so any cage for them must be completely enclosed. Groundhogs need a secure, wide open space to explore to keep their busy minds occupied. Finally, their nails grow continuously, much more quickly than ours. In order to keep them trimmed, groundhogs must keep digging or scratching on resistant surfaces.
Home Sweet Home
Groundhogs are excellent burrowers. They dig complex multi-chambered burrows used for nesting, sleeping and hibernating. The burrow is also called a cette (pronounced “set”).
A groundhog’s burrow can extend up to 1.8 m deep, 6 m wide and 19.8 m long, with multiple levels, exits, and rooms. The chamber they use for hibernation is below the frost line.
They also have a separate chamber for their waste.
A single groundhog can move over 300 kg of dirt when digging a burrow.
Their dens serve other animals too. Foxes, rabbits, snakes, raccoons and skunks often take up residence in burrows built by groundhogs.
In early June the groundhogs’ metabolism slows and their weight increases by as much as 100%. This happens because they are producing fat deposits to sustain themselves during true hibernation.
During hibernation their need for oxygen decreases. As a result, a groundhog’s heartbeat slows from 80 beats per minute to 5. Also, their respiration reduces from 16 breaths per minute to as few as 2 breaths per minute, and their body temperature drops from about 37.2 °C down to about 4 °C.
When these animals emerge in the spring, many of them as early as March, they usually have a good deal of body fat left. This is necessary because emerging so early in the season means there is very little food available.
Sparse vegetation in the spring.
Groundhogs will stand erect near their burrows on the lookout for danger. When they sense danger they emit a high-pitched squeaky whistle.
Since their top running speed does not exceed 15 km per hour, when threatened they prefer to retreat down their burrows. However if that is not possible they will climb high into a tree. They are also excellent swimmers. The groundhog tenaciously defends itself with its two large incisors and front claws when cornered.
Predators include humans, dogs, coyotes and foxes. Young groundhogs can also be killed by owls and hawks as well as snakes that can enter their burrow. It is common to see a nearly motionless groundhog standing erect on its hind feet watching for danger.
Usually groundhogs start breeding in their second year. The breeding season is from early March to late April. It is a very short breeding season so it is important that they wake up at the correct time after hibernation. Mating too early results in the growing young not having enough food to eat, and too late means the young will not be able to gain enough weight to survive winter.
A mated pair remains in the same den throughout the 32 day gestation period. The groundhog prepares a birthing den and lines it with soft grasses. The birthing chamber is usually only about 3 times the mother’s length.
Just before the female gives birth in early May the male leaves the den.
Only one litter is produced annually. The mother groundhog can have up to 10 babies, but each litter usually containing 2 to 6 young. Baby groundhogs are called kits, pups or sometimes ‘cubs’. Newborns are about 10 cm long and 30 gm in weight at birth. They are pink, blind and hairless. Their ears are folded closed and their eyes don’t yet have lids to open.
The only senses that are working in a newborn groundhog are touch and smell. The baby groundhog is very sensitive to temperature and huddles next to its litter mates and mother for warmth.
Pups consume only mother’s milk for the first 3 weeks. Then they begin to dig in the burrow and chew on things they uncover, thus learning the skills of foraging.
At 4 weeks old they have fur and their eyes are open. Their mother will now bring into the burrow flowers and soft plants for the juvenile groundhogs to chew on.
At about 5 to 6 weeks old, the juveniles begin to leave the nest to explore for short periods, all under the watchful eyes of their mother. The babies are extremely alert and will run back into their burrow if they hear their mother’s sharp, high pitched whistle.
When they are a little over 6 weeks old, the juveniles have been weaned. They are now young adults and so the mother will start moving them out of her den. At about 2 months old they are around 570 grams and are living alone in burrows they have dug.