Considered a Marmot, (Marmota monax), the North American Woodchuck is of the family Sciuridae (squirrels), despite its short tail. Approximately nine varieties or subspecies of woodchuck are recognized by scientists, mainly based on slight differences in color or skull shape. The rock-dwelling whistlers live in mountains of the far northwest, east central Alaska and British Columbia, while the common woodchuck lives in the lowlands of the central and northeastern United States, as far southeast as Alabama and Arkansas, and west into the plains states.
Physical Description
With a beaver-like appearance, the woodchuck has a broad flat skull, small rounded ears, a dark head, and beady black eyes. Adult woodchucks typically measure 16 to 28 inches long, including a 6-8 inch bushy tail, and weigh up to 15 lbs. In farming areas with few natural predators and fields of alfalfa, individual animals may grow to nearly 3 feet long and weigh over 30 lbs.
An accomplished digger, the woodchuck’s first digit of each four-fingered hand has a flat nail; the others have curved digging claws. The hind feet have five toes. Its double coat of fur is a dense wooly undercoat on the back and sides and a longer coat of silver-tipped guard hairs that make the animal appear to be “graying”. The guard hairs are banded alternating dark and light, with coloring from yellow to rusty-brown. The undercoat protects from winter cold and insulates the animals from summer heat as it thins from May to September when they undergo an annual molt from tail to head.
Like the beaver, the woodchuck’s incisors grow continually and are nearly as strong. And in the same way, the woodchuck's teeth must be worn down by correctly occluding with teeth in the opposite jaw as they chew, or the constant growth of the teeth can prove fatal to the animal.
Habitat
Typical woodchuck habitat includes farmland, fields, residential areas bordering woods, and even city parks with woody patches. They favor edge habitat near brushy woodland and unkept fields, particularly near waterways. They are also excellent swimmers and in water are sometimes mistaken for beavers. Woodchucks are less adept at tree climbing, but may do so to attain safety from a predator, or to gain access to flowers or fruit like apples and pears.
Feeding Habits
Essentially voracious herbivores, chucks may occasionally eat insects, snails, and birds' eggs, but they are primarily grazers, grazing mostly on green plants, roots, seeds and flowers. They can decimate fields of alfalfa, clover, grains and vegetables. In the fall, their largest food source is protein from acorns or other nuts for a final boost to their fatty weight before October hibernation. They often sit up and eat nuts like a squirrel. Adults also stretch up from their haunches, leverage their weight, and pull down tall plants with their forefeet, enabling them to eat the tender top leaves and seeds. They can dispose of 12-15 foot tall wild lettuce stalks in this manner.
Breeding and Reproduction
A diurnal creature, the woodchuck is a solitary animal. Shortly after hibernation in the spring, they look to breed. Two to seven young are born around May. Their skin begins to pigment within a few days and hair comes in by three weeks. They can move about and open their eyes by four weeks old and are active and weaned by six weeks. Woodchuck offspring disperse after weaning to live on their own, but do not mate until the following year.
Depending upon the location and predator density, many young chucks live short lives, surviving only a year or two. An average wild woodchuck reaching adulthood may live just five to seven years, despite their extreme wariness. The maximum lifespan of captive animals is more than three times that.
Known Predators
Information that woodchucks have excellent eyesight is debatable, since they are rodents. It is more likely they depend almost totally on their honed hearing and sense of smell, but can distinguish little by sight beyond 20-30 feet unless there is movement. Films show hunting coyotes freezing until the woodchuck resumes eating, then they attack.
Denned pups may be at risk from fishers and weasels, and depending on the area of the country, even snakes, but adult woodchucks have little to fear except from a poisonous snake. The woodchuck is territorial and a fearsome fighter, being bested primarily by canine predators. They usually hear or smell an enemy first, whether dog, coyote, or wolf, and disappear instantly down a nearby burrow. Bobcats, cougars, bears, and man are other main predators. Human hunters are an enemy that can kill from a distance unsensed; and automobiles are both too fast and confusing in sound and smell to these rodents. Like most wild animals, they have little time to develop a learning curve on the dangers of cars, before becoming their victim.
Foxes, weasels, and martens (fishers) prey mostly on young chucks, as a full-sized adult would give them a run for their money. And despite some science articles suggesting the general population of owls and hawks prey on adult woodchucks, even the largest of these raptors would struggle with the dense weight of one. Likely only the largest of Great Horned Owls or an eagle might successfully take a 15-20 pound adult.
References:
Light, Jessica E.. "Animal Diversity Web: Marmota monax". University of Michigan Museum of Zoology. http://animaldiversity.ummz.umich.edu/site/accounts/information/Marmota_monax.html. Retrieved 08-21-10.
Jones, J.K. and E.C. Birney. 1988. Handbook of Mammals of the North-Central States.
Nowak, R.M. 1991. Walker's Mammmals of the World. Fifth Edition. The John Hopkins University Press, Baltimore, pg. 499-501.
Whitaker, John O; Hamilton, W J. (1998). Mammals of the Eastern United States. Cornell University Press. ISBN 0801434750.
http://www.discoverlife.org/nh/tx/Vertebrata/Mammalia/Sciuridae/Marmota/monax/
Marie Thomas - Marie Thomas (RieT) is an author in multiple genres, with 18 years in technical writing, and freelance work in science, biographical, and ...
