Woodchucks, groundhogs and whistle-pigs

Woodchucks, groundhogs and whistle-pigs

Groundhog Day is  February 2 and according to legend if the groundhog sees his shadow there will be 6 more weeks of winter.  There are several groundhogs kept in captivity around the country that are hauled out of their dens to be weather prognosticators each year.  

Baby ground hogs.  Wikimedia commons
In 2014 New York Mayor Bill de Blasio dropped the groundhog kept at the Staten Island Zoo on Groundhog Day, resulting in her death about a week later from internal injuries. The zoo kept the death quiet, probably fearing a backlash from animal rights protectors.  But in January of the next year the zoo made an announcement that no one would be allowed to handle the groundhog on Groundhog Day, and it will be shown in a plexi-glass enclosure instead, a victory for groundhogs everywhere.

Groundhogs or woodchucks are members of the marmot family, rodents closely related to ground squirrels.  They occur in Eastern North America from Canada to Georgia.  Since they are an animal of forest edges and clearings, there are more groundhogs now in the US than there were before European settlement and the clearing of vast amounts of forested land.  The Algonquian name for the groundhog is wuchak, which is where we get the common name of woodchuck.  Woodchucks are also called whistle-pigs for their shrill whistle.

The name groundhog probably comes from the short legged, tubby body of the woodchuck and its insatiable appetite.  The woodchuck’s average weight is about 10-15 pounds on maturity but heavier animals have been recorded.  Woodchucks have broad, round bodies and short legs.  There are 4 toes on the front feet and 5 on the back.  The front feet have thick long nails for burrowing in the ground.  They have short round ears that can fold down over the ear channel when they are burrowing.  The fur is a thick gray undercoat covered with stiff outer hairs of dark gray tipped with brown or red. 

Woodchucks are diurnal animals and usually active in early morning and evening, although if the area has few humans or dogs they can often be seen out eating at any time of the day.  They often stand on their hind legs or climb up on a mound or low branch to look for danger.  If danger is spotted they move quickly into a tunnel, which they are seldom far from. Groundhogs are not aggressive to humans, livestock, or pets but they will defend themselves if cornered and their teeth are long and sharp.   Females will also protect young by trying to drive predators away.  Groundhogs are pretty solitary animals and when adults meet outside of mating season there are often battles.  Males also defend territories, which may contain the tunnels of one or more females.

The woodchuck often eats its body weight in vegetation each day.  In the fall they need to put on a thick layer of fat to survive the winter hibernation and may eat all day long in preparation.  They are primarily vegetarians, as many gardeners and farmers know. Groundhogs eat grass, weeds, garden vegetables and food crops, berries, seeds and nuts. They love alfalfa.  They will eat things like hay, chicken feed and bread scraps put out for other animals.  Groundhogs have also been seen eating grasshoppers, other insects and snails on occasion.  In turn woodchucks are food for wolves, coyotes, eagles and large hawks, bobcats and fox.  In some areas groundhogs are also eaten by humans, the top predator.

Groundhogs make a variety of noises, grunts and squeals and the high shrill whistle that signals alarm.   That short squat body can move remarkably quickly.  Groundhogs can swim well and they also can climb, often sunning themselves in low branches of trees.  They have a remarkable ability to build elaborate tunnel systems underground complete with rooms for sleeping, having babies and eliminating.  They keep the toilet areas clean by pushing wet or dirty soil out of the tunnel.  Some rooms are lined with dry leaves or grass, although the woodchuck does not store food. There are winter hibernation areas and summer bedrooms.

The main entrance of a tunnel usually begins in a brushy area, or an area where it’s disguised by a fence or building foundation.  Openings will be 6 inches to a foot or more in diameter. There’s usually a mound of soil at this opening.  The tunnel generally has several smaller “escape doors” along its route and these often have no soil mounds around them.   Tunnels go straight down at first, up to 6 feet deep, and then may stretch as long as 50 feet or more. There are built in turns or wider areas that allow a woodchuck to back in and defend a tunnel from a predator as it proceeds along it.   Tunnels are often built where soil has recently been disturbed by cultivation or for example, putting in fence posts.  Some woodchucks have several tunnels in their territory but a tunnel is usually only occupied by one woodchuck, except at mating time or when a female has young.

Groundhog tunnels are frequently used by other animals for shelter after being abandoned by their builders.  Fox, rabbits, feral cats, skunks, opossums and raccoons, none of which dig their own shelters, take over groundhog dwellings.  This makes the groundhogs important in protecting the diversity of animal life in an area, although people are often not too fond of those tunnels, which can undermine floors and foundations, destroy tree roots, break axles on farm machinery and legs on horses and cattle.

Groundhog life cycle

Groundhog really do sneak out in mid-winter, at least the males do.  It may not be February 2, depending on how far north the groundhog is living, but it’s usually late February into mid-March.  The male comes out of hibernation briefly to search for tunnels of females, one or two of which he will enter and mate with the females inside,( who must wake up briefly don’t you think?)   He will then stay in a tunnel with a female for about a month, until she kicks him out just before the babies are born.  From 2 –to 6, sometimes more, baby groundhogs are born in early spring usually just as its getting warm enough for the female to emerge and begin eating.  She’ll come out briefly to eat and then return to nurse and warm her babies until they are big enough to follow her.

Births are timed so that when the baby woodchucks come out to eat in 5-6 weeks the weather is warmer and food has become plentiful.   For a few weeks they will follow mom around and she will teach and protect them.  By late summer, however they will be scattering and building their own tunnels for winter.  A female groundhog generally does not breed until her second spring.  Groundhogs have just one family a year.  The life span of a woodchuck in the wild is 3-5 years.

How to prevent woodchuck damage to gardens, yards and livestock

Woodchucks do not normally attack people or other animals unless they are cornered or protecting young.  However they do get rabies and any woodchuck acting strangely or aggressively with no reason should be avoided and reported to your health department or animal control agency.   If you kill it save the carcass until the health department has told you what to do with it, especially if a human or domestic animal has been bitten.

Usually woodchucks cause concern when they are destroying gardens or their tunnels pose a danger.  If the animals aren’t causing damage they should just be left alone.  Check your state game laws and county regulations before shooting or trapping woodchucks.   If you trap or kill animals do it in late summer so that babies are able to fend for themselves.  Apples and carrots make good bait for live traps.  If you do trap and release you will need to take the animal a few miles away.  Realize that a great majority of live trapped and released animals will die in their unfamiliar environment anyway.

If woodchucks are eating your garden fence it with wire fencing that is loosely attached at the top so that it sways if it is climbed.  The fence should be 3-4 feet above ground in height and turned into an L shape at the bottom and extend out about two feet to help prevent burrowing.   This may not stop all groundhogs however.  A “hotwire” (electric fence), however is usually quite effective.  Place one wire a few inches off the ground and another at about 18 inches off the ground and your garden will probably be safe.  Many people do not even need wire fencing behind the electric fence. (Just make sure there are no tunnel entrances inside the fenced area.)  Small electric fence systems with battery power are available.  For some reason woodchucks rarely decide to tunnel under electric wires.  A garden inside a fenced yard that a dog regularly patrols will usually be avoided by woodchucks.  

Woodchucks will be temporarily deterred by flashing pie tins, balloons, radios, and other such scary things, but like birds they soon learn to ignore such things.  A motion detecting water sprinkler that turns on when animals come into the garden is sometimes effective with woodchucks.  If shooting is allowed for nuisance woodchucks in your area you can dispose of them this way, but it does take a good shot and patience to get them.  There are no poisons registered for woodchuck control.

To discourage woodchuck damage from tunneling, find all the tunnels you can and mow or trim any vegetation away from the entrances.  Exposing the tunnel openings may make them abandon them.  Look for all the side tunnel openings too.   Filling tunnels with dog feces or used kitty litter is sometimes effective. Several people have had success with pouring ammonia into tunnels.  Using wire, large stones or cement to fill tunnels may also be helpful.  Please don’t fill tunnels until July or later, so babies aren’t trapped inside.  It’s probably best to leave one tunnel opening until a day later, so animals inside the tunnel can get out.  You are trying to make the groundhogs or some other animal in the tunnel leave, rather than burying it alive.

When you fill up a tunnel keep an eye out for new tunnels being dug where you don’t want them.  Promptly deal with them to prevent the groundhog from getting established.  Also fill any tunnels even if you don’t think they are being used. People who own livestock should frequently check pastures for tunnels that animals could step into.  Generally however woodchuck tunnels run along fence lines, through tree lines or brushy areas where animals aren’t running through.  Groundhogs rarely tunnel through closely grazed or mowed pastures.


Some people enjoy watching the antics of woodchucks and have even tamed them enough to eat out of their hands.  Wildlife experts warn that baby woodchucks may be tame when young but as adults with no fear of humans, they can be quite aggressive so woodchucks aren’t recommended as pets.  It’s also unkind to get woodchucks used to a friendly dog, because most dogs they meet won’t be quite so friendly.  All animals have a place in the environment.  Whenever possible try to live with other creatures instead of trying to eliminate them.

No comments: