Moles and groundhogs -- also known as woodchucks -- can be identified by their appearance, their behaviors and habitats and the types of damage they cause. Once identified, these garden pests can be controlled to minimize damage to your landscape.
The most common mole pest in home landscapes is the eastern mole. Its range consist of the eastern and central portions of the U.S. Eastern moles are 5 1/2 to 8 inches long. The fur is charcoal gray with white or orange patches on the underside. The front feet are large, webbed and with claws for digging, while the snout is short with prominent nostrils. Moles do have eyes but they are hidden under their fur. They have no external ears and a short, hairless tail.
Groundhogs are much larger with a head and body averaging 16 to 20 inches and a furry tail that is 4 to 7 inches. They have grayish brown fur, short legs on a stout body and front feet with long curved claws for digging burrows. Groundhogs range consist of north into areas of Alaska, southward to northern Alabama and southern Virginia and westward into northern Idaho.
Moles spend most of their life underground and rarely come to the surface. They dig long tunnels from their dens while hunting insects such as white grubs and earthworms, but they also eat some plant material such as tubers and seeds. Moles are active year-round.
Groundhogs come out of their dens to feed mainly in the early morning and evening hours. They are herbivores that eat a variety of vegetables and grasses. Groundhogs can be active during daylight hours and are sometimes observed basking in the sun on warm days. They communicate through distinctive sounds including whistles, squeals, clicks and barks. Groundhogs hibernate in winter months.
Moles dig tunnels about 5 to 8 inches below the surface of the soil. The tunnels are about 1 1/2 inches in diameter and connect to underground dens or chambers. The excavated soil is often thrown out, creating small mounds of dirt or molehills. The molehills are usually 4 to 8 inches high. The mole tunnels can be identified by ridged-up surfaces of soil that can be followed.
The main opening of a groundhog burrow is 10 to 12 inches with a mound of dirt in front. They are often near a tree base, building foundation or fence. Secondary entrances may be present that do not have the thrown-out dirt mounds. Groundhog tunnels are as deep as 5 feet and range in length from 8 to 66 feet. The tunnels are too deep to be followed like mole tunnels.
Surveying the Damage
Moles eat harmful lawn pests such as white grubs, but many people do not like the unsightly raised tunnels and molehills they create in manicured landscapes. They may damage plant roots as they dig tunnels. Voles and mice often use excavated mole tunnels as passageways and cause damage by eating seeds, roots and tubers.
Groundhog mounds and burrows damage lawns, and groundhogs will gnaw or claw trunks and stems of fruit trees and ornamental shrubs. They eat a variety of garden plants such as beans, squash and peas. Damage to plants that occurs between early November and late February is likely caused by deer or rabbits since groundhogs are hibernating at this time. Groundhogs rarely carry rabies and are generally not aggressive but will fight back if cornered by a dog.
If you or your pet is bitten by a groundhog, seek treatment for rabies as a precaution.
Check the legal status of moles and groundhogs in your area before attempting control. Many states have wildlife protection laws that limit the methods you can use. There are nonlethal techniques that involve habitat modification or exclusion. Wire mesh fences that are 24 inches high and buried 12 inches in the ground can protect small areas such as seed beds from moles. Groundhogs require a fence at least 3 feet high and buried 2 inches in the ground. Remove food sources and disrupt burrows and tunnels to further discourage activity. Groundhog burrow entrances can be closed off when empty, and mole tunnels can be packed down with a roller.
Consider tolerating the presence of the mole or groundhog. Moles eat lawn pests and help aerate the soil. Groundhogs are a natural part of the ecosystem and food source for foxes, hawks and eagles.
- Internet Center for Wildlife Damage Management: Moles
- University of Illinois Extension: Living With Wildlife in Illinois, Eastern Mole
- Internet Center for Wildlife Damage: Woodchucks
- University of Missouri Extension: Controlling Nuisance Moles
- Internet Center for Wildlife Damage: Woodchuck Control
- Humane Society: What to Do About Woodchucks
- Huffington Post: Groundhogs in Your Garden: What You Should know About the Woodchuck
Carolyn J. Randall
Carolyn J. Randall has more than 15 years of experience in writing and publishing. She is the owner of Randall & Associates Publishing, which specializes in natural science publications related to pest control, food safety, public health, biology, plant pathology and forestry. Randall holds a Ph.D. in forest pathology.