J&T's Critter Care & Wildlife Education Center
Rescue, Rehabilitate, Release, Educate
Woodchucks
Marmota monax
Kingdom: Animalia
Phylum: Chordata
Class: mammalia
Order: Rodentia
Family: Sciuridae
Genus: Marmota
Species: monax
Woodchucks are a member of the squirrel family (rodents). I personally think they are adorable! (lol) There are about 9 subspecies of woodchucks. They are also called groundhogs, or whistle pigs.
Woodchucks are mainly herbivores. Rarely they will eat insects, snails & bird eggs. They are primarily grazers. They eat the vegetative part of plants, which is also unlike many other members of their rodent family, which feed on the reproductive parts of plants, such as seeds, nuts & flowers.
Weight range is 4-14lbs (both sexes). Length 16-27". Tail length 3 & 3/4" - 7". They have short, stocky legs and are quite strong when they are grown. Like squirrels, woodchucks have 4 toes with claws on each front paw, and 5 toes with claws on each back paw.
In the wild, woodchucks live 5-6 years. In captivity, they can live about 10 years. The oldest wild record of a woodchuck is 6 years.
Breeding season is March & April. Woodchuck gestation lasts about 30 days, with gestation of 31-33 days also have been recorded in studies. The number of young range from 2-7, with an average litter being 4.6 young. Newborn groundhogs weigh about 30g and are about 4.25" long.The young wean at about 6 weeks of age. Both male & female woodchucks reach sexual maturity around 1 year of age.
Woodchucks prefer sandy areas - maybe because it is easier to dig?? I don't know:) They can be territorial with their home den, however, some do den together. Although we normally see woodchucks on the ground, they do climb quite well.
Woodchucks go through one annual molt. The molt begins around late May and will continue through September. The molt begins at the tail and will progress forward to the head.
An unusual thing I found about woodchucks through researching info for this page, was that they do not get the dark yellow pigment to their teeth that is charateristic of other rodents. Their teeth formula is 1/1, 0/0, 2/1, 3/3. In woodchucks, malocclusion is apparently common.
Woodchucks also posses anal glands that secrete a musky odor.
Woodchucks are very vocal animals. They have seveal sounds they make, including a loud shrill whistle when alarmed. They also grind their teeth & chatter when they are cornered.
Dens are preferred in well-drained areas. They are true hibernators. They rely on body fat to sustain them during this time. Woodchucks have been studied in hibernation studies. Woodchucks normally fast through the winter, denned up in their burrow. During their hibernation, they roll themselves into a ball. There are some that wake during the winter. The oldest & biggest woodchucks go into hibernation first. They are followed by yearlings & juveniles. Woodchucks close up the hole to their den in the winter. They use dirt, vegetation & fecal materials to plug the hole. When hibernation has ended, the largest woodchucks emerge from the dens first. I read that woodchucks loose approximately 30% of their body weight, and weight loss will continue for the first few weeks out of hibernation.
When they first emerge from their dens, green vegetation can be limited, and during this time, they may eat bark, buds, & twigs of plants like dogwood, sumac, black cherry and other fruit trees. Favorites include grasses & forbs, clover, leaves of sassafras and other trees, and numerus herb trees. They are partial to many farm crops too, such as, alfalfa, soybean, planted clover, corn, oats, & assorted fruits and vegetables.
The daily food consumption can be as much as 1-1&1/2lb.
The woodchuck has many predators, such as wolves, coyotes, large hawks & owls, and smaller woodchucks may be eaten by various snakes.
Impact/Negative:
Woodchucks can be serious agriculture pests. They can travel a signifcant distance to raid gardens/crops. They make large den holes, that farm machines have been damaged in. Digging around or under foundations to buildings can ruin them. Horses have also stumbled in the holes & have broken legs.
To keep woodchucks out of your gardens, extend the fencing underground 1&1/2 - 2ft. Or, you can extend the bottom out across the ground (at ground level) and cover it with dirt. Extend the fencing out at least 18".
To ensure woodchuck control, you need to understand the woodchucks dens. Woodchucks create 2 kinds of dens - the winter den, and the summer den. (Simple huh? :) Inaffective control usually happens because all of the dens are not found. Winter dens are usually located in woodsy, or brush areas. They most often serve as the hibernation den. Although, some woodchucks may use a hibernation den all year. Hibernation dens will have 1 opening. The hibernation area is usually located under a stump, or something similar, to aid in protection. Most often, the hibernation den is abandoned within a few weeks of re-emergence at spring. Woodchucks then begin their summer dens. These dens are usually in fields, or maybe crop areas. Crops areas they may burrow in, include, soybean, clover, alfalfa, and corn. I've read these are some of their FAVORITE crops. Summer dens may have 1-5 openings. The woodchuck usually has 1 main entrance, with several escape routes, in case that he made need it. These escape holes are called "plunges". They usually hide these plunge holes very weill in the vegtation, and they may even be plugged! If the same woodchuck, or generations of several woodchucks have used the same burrows repeatedly, the tunnel systems can be very complex, very long and contain several holes. Woodchucks may even make more then 1 summer den in a field/crop area. Generally, they have the "home" den, and the other den is often used as an escape route. An average woodchuck den is 2-4 ft deep and will run 15-25 ft or MORE horizontally. The main den will usually be located at the end of the tunneling system, but other nests can be located anywhere along the burrow line. The woodchuck's main entrance has a characteristic dirt mound. When other animals, such as skunks, rabbits, foxes or badgers, are using the tunnels, the dirt mound will be absent. These other types of animals will often leave scat near the entrance as well. If the den is in a good foraging area (such as a crop field), the woodchuck usually forages close to home (maybe 20-30yds). In less than adequate foraging areas, the woodchuck may roam several hundred yards to forage. Usually 1 adult woodchuck will den per acre. They will protect their dens against other adult woodchucks.
I am not going to include exclusion methods here, as they are easy to find on the net. However, I will report, that like with all animals, I advocate HUMANE removal of nusiance animals. Removal when needed.
Another note: If you live capture (be sure to check your local laws! Usually, you can't "just" trap, or kill animals), be sure not to touch any wild animal! Aside from diseases, animals that are captured are scared! Chances are they WILL bite to protect themselves! (Can you blame them???)
Impact/Positive:
Woodchucks are important to the ecosystem. Their abundance provides food for larger predators. They also influence how many, and what type of plants grow in areas by eating them. They are also a target of sport hunting (which I do NOT advocate to let you know), which can help control the population. Their reproduction has thus far kept them from extermination. Their burrowing activity provides homes for various types of wildlife. Vegetation growth around burrows is usually abundant, due to fertilization from the buried fecal materials of the woodchucks. The burrowing also aerates & mixes the soil. They can also be very entertaining to watch. They are often a favorite of many wildlife observers.
Woodchuck prints: (not my photos! :)
*** J&T's Critter Care & Wildlife Education has obtained licensing for their first non-releasable animal! We have a woodchuck! You can learn more about him here.
References:
Journey North 1997: Signs of spring Everywhere
Pennsylvania Game Commission - State Wildlife Agency - Wildlife Notes - Woodchuck
Wild Marmots Photo Gallery by Christina Craft
Marmot Wildlife Notebook Series Alaska Dept. of Fish & Game
Hinterland Who's Who - Woodchuck
ADM16 - Woodchucks - Animal Damage Management - Dept. of Entomology (PDF)
Living with Woodchucks - Nebraska Wildlife Rehab, Inc (PDF)
Massachusetts Audubon Society - Woodchucks