A Groundhog explores the marsh at Milliken Park

On a spring day, Bob and I visited Milliken Park, in Toronto, to see what’s new. In light of all the migrating birds returning from the south, we thought perhaps we might spot some warblers or sparrows. Instead, Bob observed an Opossum scurrying for its den just as a heavy downpour descended upon us, while I was witness to a Groundhog (Marmota monax) dashing across an open expanse of grass and then taking cover in thick underbrush.

We began our walk, as habit has it, around the perimeter of the main pond and then progressed to the north end of the park where a small wetland is bordered by ornamental shrubs, deciduous trees and evergreens. Very often, we see Groundhogs grazing on the fresh grass on the hillocks west of the marshy area, as well as Cottontail Rabbits. A major effort was made last year to naturalize the area adjacent to the wetland with hundreds of newly-planted bushes and saplings. Hopefully, we will see a rise in the number of wild animals living in the expanded habitat.

Groundhogs are a fairly common sight, but, honestly, I have never before had the opportunity to take in their physical characteristics and behaviour in such close proximity. This Groundhog thought he was well hidden when it hunkered down at the edge of the stream and began lapping some water. Seeing as Groundhogs usually hydrate by eating leafy plants, this seemed atypical.

Groundhogs are rodents belonging to the squirrel family, Sciuridae, and are classified as marmots. They are the largest members of the squirrel family in their geographical range, although among North American rodents, beavers and porcupines are larger. Groundhogs are stocky little animals that weigh 2-4 kilograms (4-9 lb) with a length of 40-65 centimetres (16-26 in) which includes a short, bushy tail. Before hibernating in the fall, they pack on the pounds and are considerably heavier.

Groundhogs, or Woodchucks as they are alternately called, are well suited to digging. Their legs are thick and powerful, and their feet are equipped with sturdy, curved claws. The front feet, in particular, have four strong, thick claws as they are the ones used mainly when excavating a burrow; the hind feet have five claws. Groundhogs elude predators by diving into their burrows so they have no need of running quickly. In fact, their top speed is about 15 kilometres per hour (9 miles/hr). They may appear chubby and cumbersome but Groundhogs can swim very well and are excellent at scaling trees or shrubs, another method of escaping enemies and a means of surveying their surroundings.

The fur of Groundhogs varies in colour from one region to another. The fur can be anywhere from grey to cinnamon brown to dark brown, with medium brown being the most common shade. Two coats of fur make a Groundhog well suited to our temperate climate. The undercoat is dense and grey, whereas the outer coat is composed of the longest and coarsest hairs. It is the white-tipped guard hairs of the outer coat that give a groundhog its distinctive “frosted” appearance.

I watched as this little rodent nuzzled up to a slim sapling and began chewing the bark. This surprised me because I only ever thought that Groundhogs eat grass and other tender greens. I have since learned that Groundhogs eat quite a variety of wild plant matter, even the occasional snail or insect, and in the spring, it is not uncommon for them to eat bark and small branches. Who knew? This explains their preference for habitat that includes open areas next to woodlands.

Groundhogs are one of the few species that truly hibernate. All summer long, a Groundhog gorges on the plentiful vegetation to build up its fat reserves. Once the first frost hits, a Groundhog will withdraw into its underground burrow where it will curl into a ball and sleep until springtime. During hibernation, a Groundhog’s temperature drops to about the same temperature as that of the burrow, and its heart rate slows significantly. Therefore, its fat reserves can sustain the rodent for the length of hibernation, which is anywhere from 3 to 6 months. Generally, they emerge from the burrow again around March or April.

A Groundhog digs its burrow deep enough to be below the frost line, and the snug environment of the underground tunnels sometimes will also provide shelter during the cold, winter months to other animals such as Cottontail Rabbits and Opossums. As a matter of fact, when in Milliken Park this past winter, we saw an Opossum descend into a similar hole in the ground. Groundhogs dig more holes than any other mammal in North America, so all sorts of creatures thrive because they can take refuge in the Woodchuck burrows. When a Groundhog is frightened, the hairs on the tail will stand straight up making the tail look like a hairbrush. As I photographed this cute little rodent, he seemed totally relaxed and finally sauntered off in the direction of the lush, green grass.

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