Urban Wildlife | Groundhogs

Biology

Groundhogs are mostly diurnal. They will often issue a shrill whistle when disturbed, so it is of little surprise that one of the synonyms for groundhog is the whistle pig.
Groundhogs breed between March and April. The litter usually consists of four to six young that are born about a month after mating. They are generally independent after mid-summer.
They are herbivorous, feeding in mid-summer. They will eat carrot tops, beans, peas, etc. They can damage trees with their persistent gnawing. They do this to keep their ever-growing teeth at a manageable length.
They can fit through holes that are 3-inch x 4-inch and enjoy denning under porches and decks. The characteristic mound of earth at the den entrance is a good indicator.
They are often associated with agricultural areas, combinations of open fields (food) and cover (woodlots and hedgerows).

They often establish burrows along grassy strips of land parallel to highways and so are usually found dead along the road.
True hibernators, they will sleep for up to five months after the onset of cold weather.
Their burrows usually have one main entrance and up to 3 secondary entrances. The tunnels are rather shallow (2-3 feet deep). Some burrow systems will remain occupied by successive generations.
To determine if a groundhog is eating your plants, look at the bitten ends. If the edges are smoothly cut on a diagonal plane, chances are you have a rabbit or a groundhog. If the edges are ragged, it is probably a deer causing the damage.

IS THERE A PROBLEM? HOMEOWNER SHOULD ACCEPT NORMAL, UNOBTRUSIVE BEHAVIOR.

Refer to SELF-HELP if:

Removal of Attractants

To eliminate possible den sites: remove rocks and woodpiles, securely close off entry under sheds, outbuildings, porches, etc.
Harvest gardens and pick up fallen fruit frequently.

Habitat Modification & Exclusion

Exclusion should only take place after the young have been weaned (late summer).
Find active burrows by stomping down the mound openings. If they are open the next day, place dog droppings or rags soaked in peanut or olive oil in the openings.
Remove all cover from around burrows.
Groundhogs are easily frightened. A beach ball placed in the yard can discourage them from the area.
Lock pet doors at night.
If the animal is confined, open a gate to allow it to leave on its own. Encourage its exit with loud noises or by spraying it with a hose.
Once the groundhog is removed, it is recommended that an electric hotshot wire be installed 4-5 inches outside the perimeter of an existing fence. Wire should be 4-5 inches above ground, and vegetation should be kept short to prevent shorting the wire.

Repellents

1 cup Castor oil, 2 cups Murphy's oil soap, 1¼ cups of the hottest hot-sauce you can find, and ¼ shot glass of human urine. Mix in one teaspoon of the solution per gallon of water and spray the area. Obviously, the measurements can be altered to suit the amount required.
Spray the animal with water from the hose.
Use Ro-Pel® or Critter Ridder® (though the effectiveness of either has not been proven on groundhogs).
Epsom salts placed near or around the runs will keep the groundhog away. If your plants are being eaten, try placing some salts near the plants.
Place ammonia-soaked rags in areas where the groundhog frequents.
Loud noises (clap hands, etc.) will usually scare it off.
For more great tips go to Groundhog Controls

In the case of a bite: If a domestic pet has been bitten, bring the pet immediately to the vet. In off-hours, emergency cases can be brought to DMV, a 24-hour veterinary service. However, this clinic, though extremely thorough and knowledgeable, is also quite expensive. If a human has been bitten, bring them directly to a hospital.
Maintain minimum contact and keep pets at a safe distance.