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Groundhogs are pretty popular when it comes to predicting the weather and bothering golfers in movies. But their love for plants and vegetables don't make them very popular among homeowners who have them as neighbors.

We can thank the Pennsylvania Dutch for the yearly tradition of looking to a groundhog for predictions of when spring might arrive.

Supposedly this derives from a German tradition of where a badger was the weather-predicting mammal. I guess groundhogs were way more common in Pennsylvania.

Despite the adorable pictures of groundhogs seeing their shadows or not on Feb. 2, if you’ve had a groundhog move into your yard I doubt you find them cute.

Groundhogs, a.k.a. woodchucks or whistle pigs, can be nearly impossible to evict once they decide to move in. They are stubborn, strong and can be dangerous if cornered.

Groundhogs are a common sight across Illinois. You might be surprised to learn they’re rodents and cousins to squirrels. Their large incisors grind, chatter, and make a shrill whistle when threatened. This is how they earned the common name "whistle pig."

Typically, groundhogs are about 17 to 26 inches long and weighing anywhere from 7 to 14 pounds. Given an abundant food supply though, they can grow up to about 32 inches long and weigh a whopping 30 pounds. Judging by some of the well-fed groundhogs I’ve encountered, this is a pretty accurate statement.

Groundhogs have powerful, clawed front legs that are well-adapted for digging. If they are cornered, they can use these same strong front legs to defend themselves. When excavating a new burrow, it is estimated that a groundhog moves about 35 cubic feet of soil.

Groundhogs usually dig at least two burrows over the course of a year -- one or more summer burrows and a winter burrow. They live alone except during the breeding season in early spring. Usually, only one or two adults will occupy an acre of land, unless the habitat is exceptional.

The summer burrow is the most extensive; it contains up to 45 feet of tunnels that may be as deep as five feet underground. Groundhogs prefer to situate the summer burrow on a grassy slope in an area with sandy, well-drained soil. Keep an eye out along roads and railroads with grassy shoulders this summer, and I guarantee you'll spot a groundhog or two.

The summer burrow contains a main chamber for sleeping, and one used as a bathroom. Groundhogs are diurnal, meaning they are active during the day, so it’s not unusual at all to see them out and about throughout the day.

It’s what groundhogs do while out and about during the day that annoys homeowners, particularly gardeners.

Groundhogs are primarily herbivores, feeding on plants. They especially love fruits and vegetables, but they will occasionally eat insects, snails and bird eggs. A home orchard or vegetable garden is truly the promised land for a groundhog. He will eat about 1 1/2 pounds of vegetation each day, and I guarantee it will be whatever you have been watching and waiting to eat yourself.

Groundhogs are one of the only true hibernating animals in Illinois. Around October, they begin hibernation in a separate winter burrow. This burrow is typically in a wooded area and is much shorter, with only one opening. At the end of the winter burrow is one nest chamber. The groundhog blocks this section off with soil once he is safely inside for the winter.

Hibernation is a pretty amazing feat. The groundhog’s body temperature drops from about 97 degrees to 34 degrees. It only breathes once every six minutes, and its heart beats only four times per minute. In a process that is not completely understood, the groundhog’s internal clock tells it when to wake up in the spring. Scientists believe the outdoor temperature is a factor involved in the waking process.

So what do you do when one of these giant hibernating rodents decides your yard is its new home? Unfortunately, the only way to control groundhogs without a permit is to exclude them from a given area. This sounds deceptively easy. A simple fence will not work. Not only are groundhogs excellent diggers, but they are also good at climbing, too.

Fences need to be at least three feet tall, with the top portion angling outward at a 45-degree angle to prevent the groundhog from climbing over the fence.

That same fence needs to extend underground 12 to 14 inches with the lower two to four inches angled out at a 90-degree angle to prevent the groundhog from burrowing under the fence.

As an additional deterrent, some sources recommend placing an electrified wire four to five inches above the ground outside the fence.

A lot of people throw up their hands and surrender their garden to the groundhog community when they read these fence criteria. Most people don’t want to have their yard on lockdown.

I have heard some anecdotes about placing highly “fragrant” materials like fresh manure near the burrow entrance to encourage the groundhog to move elsewhere. While I haven’t found any research to back up this method, if you can stand the smell, it certainly wouldn’t hurt anything, so why not try it?

Groundhogs don't venture very far from their burrows -- only about 50 to 150 feet. If they have burrowed into material that can be removed from the site, they may move on if that material is removed. I have seen situations where groundhogs have moved into piles of junk and brush on a property, and getting rid of the piles also got rid of the groundhogs.

Groundhogs prefer areas that don't have a lot of human activity. Increasing human activity in an area, or using props like scarecrows, as long as they are often moved, may help encourage the groundhogs to find a new home.

Many homeowners mistakenly assume that since they can buy a trap big enough for a groundhog, that it’s perfectly fine to go ahead and trap them. The law says a person may not use any trap, even a live trap, to capture a groundhog without an animal removal permit from an Illinois Department of Natural Resources district wildlife biologist. Find instructions for obtaining permits on this University of Illinois Extension website:

Furthermore, a groundhog caught in a live trap must be released or euthanized within 24 hours of capture. To release the animal on property other than your own, you need written permission from the landowner in addition to the permit from IDNR. As with all other mammals, it is not permitted to release groundhogs in public parks, forest preserves or natural areas.

You can buy carbon monoxide gas cartridges to kill groundhogs in their burrows. But again, you still need to obtain a permit from the IDNR to use them.

Most homeowners find it a lot easier to hire a nuisance wildlife control operator to trap and remove the animal. But if you can tolerate the animal’s presence on your property, it is also a valid choice to just leave the groundhog alone.  

Jennifer Schultz Nelson is a unit educator in horticulture for the University of Illinois Extension.


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