Woodchuck

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Woodchuck
Groundhog/Eastern Marmot/land-beaver
Marmota monax

Scientific classification:

    Kingdom: Animalia
    Phylum: Chordata
    Class: Mammalia
    Order: Rodentia
    Family: Sciuridae
    Genus: Marmota
    Species: M. monax

Woodchucks are the largest member of the squirrel family, a large marmot (ground-living rodent). With a stout body (Length: 16-30" includes 6" tail) and short legs which give the woodchuck a low to the ground appearance (Weight: 4-20 Lbs).

They are a grizzled brown which varies from reddish to blackish, and uniformly colored. They have two coats of fur (a good idea in Minnesota). A dense grey undercoat and a longer coat of banded guard hairs that gives the groundhog its distinctive "frosted" appearance. Prominent bushy tail, large black eyes, small ears, sometimes an area of white fur around its nose, and darker brown or black feet. The front feet have 4 clawed toes and the hind feet have 5 clawed toes, which are well adapted for digging, with short but powerful limbs and curved, thick claws. The Woodchucks spine is curved, more like that of a mole. Unlike the squirrel, the tail is only about 1/4th the body length. Its sight, hearing, and smell are all reported to be keen.

The woodchuck has a distinct pattern of teeth. There are 4 large incisor teeth for biting off vegetation and gnawing through roots when tunneling. These teeth keep growing, about 1/16" per week. Constant usage wears them down again by about that much each week. A gap in the teeth follows, then eighteen chewing teeth. These enable the woodchuck to grind up the vegetation he is eating. The jaw can move from side to side as well as up and down, making chewing easier.

Diet

Woodchucks primarily eat wild grasses, legumes, tree bark, clover, alfalfa, plantain, corn and other vegetation, berries and agricultural crops when available. Woodchucks also eat grubs, grasshoppers, insects, snails and other small animals, but are not as omnivorous as many other sciuridae. Like squirrels they also have been observed sitting up eating nuts such as shagbark hickory but unlike squirrels do not bury them for future use. They have the ability to destroy an entire garden or flowerbed in a relatively short time.

Woodchucks are generally found in pastures, meadows, old fields, and wooded areas and frequent the areas where woodlands meet open spaces, like fields, roads, or streams.

Burrows

Woodchucks are excellent burrowers, using burrows for sleeping, rearing young, and hibernating. The average Woodchuck has been estimated to move 35 cubic feet (710 lb), of dirt when digging a burrow. Though woodchucks are the most solitary of the marmots, several individuals may occupy the same burrow. The burrows usually have two to five entrances, providing woodchucks their primary means of escape from predators. Burrows are particularly large, with up to 46' of tunnels buried up to 5' underground, and can pose a serious threat to agricultural and residential development by damaging farm machinery and even undermining building foundations. Defecation inside the burrow, in a special excrement chamber separate from the nesting chamber, fertilizes the earth. Digging also loosens and aerates the soil, letting in moisture and organic matter while bringing up subsoil for transformation into topsoil.

In the spring, occupied woodchuck burrows are easily recognized. Large burrow openings, 812" across, with mounds of dirt just outside main entrance. Often additional escape openings flush with the ground, with no mounds. Fresh dirt pellets, ranging from marble size to clods about as big as a fist, are generally found at the mouth of an active burrow. Clawed or girdled trees and shrubs also help identify woodchuck inhabited burrows and dens.

There is a separate summer and winter den, which will often be sheltered by trees or shrubs. The woodchuck prepares a nesting chamber, where he can sleep, and also makes a separate excrement chamber for his toilet needs. Old woodchuck burrows may be used by other animals, such as skunks, rabbits, raccoon, and fox. Sometimes enlarging it to create a nursery den.

Behavior

Outside their burrow, individuals are alert when not actively feeding. It is common to see one or more nearly-motionless individuals standing erect on their hind feet watching for danger. When alarmed, they use a high-pitched whistle to warn the rest of the colony, hence the name "whistle-pig". Woodchucks may squeal when fighting, seriously injured, or caught by an enemy. Other sounds woodchucks may make are low barks and a sound produced by grinding their teeth.

A Woodchuck is active by day, especially in early morning and late afternoon. Despite their heavy-bodied appearance, groundhogs are accomplished swimmers and excellent tree climbers when escaping predators or when they want to survey their surroundings. They never travel far from the den. If alarmed, the Woodchuck often gives a loud, sharp whistle, followed by softer ones as it runs for its burrow, from which it then peeks out. When agitated, it chatters its teeth, and it can hiss, squeal, and growl. They prefer to retreat to their burrows when threatened; if the burrow is invaded, the groundhog tenaciously defends itself with its two large incisors and front claws. Groundhogs are generally agonistic and territorial among their own species, and may skirmish to establish dominance.

Hibernation

Woodchucks are one of the few species that enter into true hibernation, and often build a separate "winter burrow" for this purpose. This burrow is usually in a wooded or brushy area and is dug below the frost line and remains at a stable temperature well above freezing during the winter months. In late summer or early fall, the Woodchuck puts on a heavy layer of fat, and are at their maximum weight shortly before entering hibernation, which sustains it through hibernation. It digs a winter burrow with a hibernation chamber. After the first frost, the woodchuck seals the sleeping chamber entrance with dirt, then curls up in a ball on a mat of grasses. Where the animals body temperature falls from almost 97F to less than 40F , its breathing slows to once every six minutes, and its heartbeat drops from more than 100 beats per minute to four. In Minnesota, woodchucks hibernate from October to April, but in warmer areas, they may hibernate as little as 3 months. They emerge from hibernation with some remaining body fat to live on until the warmer spring weather produces abundant plant materials for food.

Reproduction

The male emerges in early spring and seeks out females in its territory, (hence the famous Groundhog Day*) pairs meet but don't mate at this time; the male returns to his burrow for another month's sleep, mating with the female he has earlier encountered when he made his first emergence. The second time, the woodchuck awakens, it is time to move to the summer den and to begin eating the tender vegetation that appears. There is a brief mating season. Then the mated pair remain in the same den throughout the 2832 day gestation period. As birth of the young approaches May-June, the male leaves the den.

The female gives birth to a litter of 26 which are blind & furless. They are helpless for about a month. Then they begin making short trips outside of the burrows to eat grass and clover. At about 5-6 weeks of age the young woodchucks are weaned and ready to seek out their own dens.

Usually groundhogs breed in their second year, but a small proportion may breed in their first. One litter per year. Woodchucks usually live from two to three years, but can live up to six years in the wild. In captivity, groundhogs can exceed this limit as, the 22-year-old Wiarton Willie may indicate the maximum lifespan. Common predators for groundhogs include wolves, coyotes, fox, bobcats, bear, large hawks, owls, and dogs.

Track foreprints are 2" long, showing 4 long toes; hindprints similar but longer when heel leaves impression in soil, and showing 5 toes. Trail is usually found in disturbed earth around burrow. Scat droppings variable, usually more than 1" long.

Groundhog Day: Legend says that if the groundhog, or woodchuck, emerges from his den on February 2 and sees his shadow, 6 more weeks of winter will follow. The legend was brought here by German immigrants from Europe, where it was the badger whose emergence from his den foretold more winter to come. Nowadays, people enjoy having Groundhog Day celebrations, but they don't have any relation to actual weather forecasting. In Minnesota it is pretty much a given that there will be 6 more weeks of winter.

Tongue Twisting Riddle:
How much wood, would a Woodchuck chuck, if a Woodchuck could chuck wood?

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