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Nature Notes: Groundhog

Ed Robinson
May 28, 2014

Talk about an identity crisis! This animal is known by a variety of names, none of them grounded in biology. “How much wood would a woodchuck chuck?” None — they don’t eat wood! The confusion probably arose because the Algonquians called this creature “wuchak.” Despite being referred to by some as a “land beaver,” they are not related to those industrious dam builders. He may be called “whistle pig” because of his sharp whistle used to warn neighbors about a nearby predator. “Groundhog” is his generally accepted name, but these lowland creatures are unrelated to pigs. To top it off, city dwellers seem to think groundhogs naturally live in glass enclosures in Punxsutawney, PA and have a gift for forecasting the end of winter. What’s a poor groundhog to do?

Let’s start by noting that the groundhog is a rodent, more specifically a large ground squirrel, part of the marmot family (scientifically, he is Marmota monax). When you see the large front teeth, you can understand the rodent identity. Lumping groundhogs with squirrels seems a bit of a stretch, unless you have seen a groundhog climb a tree, as they do readily, either to escape a predator or to snack on buds and new leaves. While most of the 13 smaller members of the marmot family live at higher elevations, and prefer rocky terrain, groundhogs prefer open farm country. They can swim quite well, allowing them to cross streams while searching for a new territory.

Laurel Locke photo

Laurel Locke photo

Groundhogs are found across the US and Canada, from Alaska to our southern states. Far from being endangered, it is estimated that there are more groundhogs living today than when our country was first settled, thanks to farmers who cut large swaths of forest for cultivation. Their preferred habitat is open fields, hedge rows and forest edges where they dig their burrows.

Groundhogs are not a favorite of most farmers, since the entrances to burrows can damage farm equipment and livestock can break their legs falling into the holes. Gardeners must be on their guard for a marauding groundhog, since they can lay waste to your hard won crops in no time.

Groundhogs are eating machines, consuming up to 1.5 pounds of food per day. Over a life span of 3-6 years in the wild, a groundhog can exceed 2 feet in length, with a short dark brown tail, and in ideal habitat have been known to reach 30 pounds. Their diet is mostly vegetarian — clover, alfalfa, wild grasses, berries, soybeans, garden beans, peas and carrot tops. They occasionally will eat nuts, grubs, grasshoppers, snails, insects and even young birds found in a ground nest. Once settled in a good spot, groundhogs will have a limited range of only a couple hundred yards as long as adequate food supplies are available. All that food goes to building fat reserves for a long winter siesta, since the groundhog is a true hibernator.

A number of predators will snatch a groundhog for a nutritious meal, including coyotes, foxes, bobcats, bears, eagles and dogs. Young groundhogs may be taken by larger snakes, which enter burrows looking for food. While the animal is tough and equipped with sharp teeth and claws to give a good account of itself in a close quarters battle, its primary defense is a large burrow system with multiple exits. Researchers have excavated groundhog burrows with up to 50 feet of tunnels, and multiple chambers, including a separate toilet room for hygiene. Deep winter burrows are dug below the frost line, allowing the groundhog to sleep through the cold season in a reasonably warm nest, protected by a heavy coat.

Most groundhogs begin breeding in their second year, from late February to late April, depending upon the location. The males are polygynous, a nice way of saying they will breed with a number of females, before pairing up with one until her litter is born in April or May (gestation is about 32 days). Between 2 and 6 babies are born blind, hairless and helpless. Once the young have grown hair and can see well, the female takes them out of the burrow to show them how to survive. Weaning takes place at around 6 weeks and the young are encouraged to move on to find their own dens.

Given the problems that a groundhog may cause by chowing down your garden or weakening your stone foundation with his digging, you might ask what role the groundhog plays in nature. All that digging can aid soil mixing and aeration, and the animal is productive in converting vegetation to fertilizer. When a groundhog passes on to that big alfalfa field in the sky, feeding a number of creatures with his remains, the burrows left behind become homes for creatures less able to dig their own — fox, rabbits, raccoons, skunks, weasels, opossums, and snakes. So when you see a corpulent groundhog standing guard at his burrow, give him a wave or a whistle, and enjoy him as he goes busily about his work.

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