I used to have a female groundhog living under my shed, which provided amazing opportunities to watch an active den and study groundhog behavior up close.
Groundhogs are extremely common in many parts of north america, so let’s explore some key facts to help interpret their activity in the likely event that you encounter one.
Watch this video with some fantastic clips I got of the mother groundhog and her babies to get started:
I also have some additional details about groundhogs organized below on mating, hibernation, vocalizations and other behaviors.
What Is A Groundhog Exactly?
Groundhogs are a type of large ground squirrel that is extremely common in eastern north america, where it is also frequently known as the woodchuck.
Groundhogs are about the size of a cat, but more plumped out and rotund. They have small ears and eyes, and a small tail. Their body is a mixture of shades of brown.
They are very similar to the marmots that live in mountains on the west coast.
On this female groundhog mother, the tail is darker and she has a reddish underbelly. The lightest fur occurs on her face, which contrasts against her darker eyes.
The main difference in appearance from other similar animals like ground squirrels or gophers is size. Groundhogs are much bigger than the other types of ground squirrels common to pastures and deserts of western regions.
Groundhogs are diurnal mammals, which means they do all their activity during the daylight hours.
Groundhog Habitat: Where Do Groundhogs Live?
Groundhogs live in underground burrows in open fields that edge against forests to the north and east of the great plains. They also occur in similar habitats in the northwest.
Groundhog Dens And Burrows
In loose soil conditions, groundhogs will dig networks of tunnels underground with multiple entrances. The main entrance often has noticeable signs of excavation, but secondary entrances can be much less obvious.
The holes are big (approximately adult hand-sized) and occur in clusters with multiple entrances and exits spreading out around the territory.
In places with rocky and hard to dig soil, groundhogs will also have dens underneath human structures like sheds or decks. These groundhogs may need to leave in winter in order to hibernate in a different location.
Groundhog Diet: What Do Groundhogs Eat?
Groundhogs are herbivores with their main diet being green vegetation. They’re particularly fond of agricultural crops like alfalfa and common vegetables of home gardens like lettuce & peas.
They will eat pretty much any green vegetation that’s easy to access, but will focus on their favorite foods first.
Common Groundhog Behaviors
Most of the time when you see groundhogs they will either be eating or engaging in vigilance behaviors like watching & listening.
Groundhogs spend a lot of their time standing guard for predators like cats, foxes, coyotes or other dangers.
If you spook a groundhog while walking near their territory they will run to the nearest hole for safety. They may also make alarm calls directed at you or other nearby perceived dangers (more on this in the section on vocalizations).
Groundhogs will even climb up onto trees and boulders and it has been reported that they are capable swimmers. (I assume this would only be in unusual circumstances like escaping a predator or during seasonal movement).
Groundhogs also spend a lot of time underground. They typically only have one period of above ground activity per day, but in hot weather they may have two shorter periods in the morning and evening.
In winter, groundhogs hibernate for 3-6 months in underground burrows. Sometimes these are the same burrows they use in fields during the warm season. Other times they move into forests to dig their hibernation dens.
The trigger for hibernation is cold and lack of food on the landscape. As such, groundhogs hibernate much longer in northern and colder regions than they do in southern areas.
Groundhogs are true hibernators which means they go into deep sleep and slow their metabolism. This makes it possible for them to go many months without food or water.
Groundhog metabolism responds to the surface temperatures from deep within their hibernation den, and if the temperature warms up enough, they will be forced out of hibernation and into the world in search of food.
This commonly happens while there is still snow on the ground, and explains why groundhog day is celebrated in early February.
When Do Groundhogs Mate?
Groundhog mating happens within the first few weeks of their emergence from hibernation in very early spring or late winter. This can even happen while there is still snow on the ground.
One month later, the female groundhog gives birth and raises her babies alone. After about a month of nursing inside the birthing chamber, the young groundhogs start to poke their heads out and explore the area just outside the den.
I got to watch two families of baby groundhogs be born under that shed. The first year there were two babies, and the second year there were three.
The babies only stay with their mom until early summer (sometime around July) before heading out on their own.
In my case, they were only present in this den for a few weeks in spring and once they were old enough to travel, she took them to a different location.
Groundhogs are known to make a wide variety of whistling and screaming sounds, which lead to another common naming, the whistle pig.
Despite watching them every day for several months, I only ever observed one instance of a groundhog making calls, while standing at the entrance to an escape hole. If danger came close, it would suddenly run back inside.
Their calls are similar to chipmunks, and could be confused with each other.
Are Groundhogs Friendly?
Groundhogs are quite happy to share territory with humans, as long as you respect their space and watch from a distance.
They are wild animals, so don’t expect them to come too close. If you do scare them into their holes on approach, don’t feel bad.
My groundhogs would often run into their holes when they first saw me walk outside, but if I sat still for a few minutes they would come out and happily explore within 10-20 feet of me.