The sudden appearance of holes in a yard or garden often creates a mystery regarding the unseen animal responsible for the excavation. Understanding the differences between these subterranean disturbances is the first step toward deciphering the animal’s behavior, whether it is foraging for food or establishing a permanent den. Accurate identification provides clues about the size, intent, and species of the hidden architect. By closely examining the characteristics of the excavation, one can determine the nature of the animal’s activity.
Key Characteristics for Identification
Observing specific physical evidence left behind by the digging animal is required for identification. The diameter of the hole offers the first clue, as a small opening points to a different culprit than a large entrance. The shape of the hole is also telling; entrances can be round, conical, or funnel-shaped, depending on the animal’s digging technique and purpose.
The location provides further context, as some animals prefer open lawns while others favor areas near structures or dense brush. A distinguishing feature is the presence or absence of a dirt mound adjacent to the opening. If a mound exists, its shape and composition are informative, ranging from a symmetrical cone to a larger, irregular fan of coarse soil.
Distinguishing Moles and Pocket Gophers
Moles and pocket gophers are frequently confused subterranean pests, but their digging methods and resulting structures are distinct. Moles tunnel primarily to hunt for food, specifically earthworms and insect larvae, resulting in extensive but often shallow tunnels. Their surface activity is marked by raised ridges, or runways, that snake across the lawn. When moles push soil from deeper tunnels, they create volcano-shaped mounds that are small and symmetrical, often with a plugged central opening.
Pocket gophers are herbivores that dig to access plant roots and tubers, creating deeper, more structured tunnel systems. Their mounds are larger and flatter than those of moles, forming a crescent or fan shape as the gopher pushes soil out laterally. The entrance hole is usually offset to one side of the fan-shaped mound and is almost always plugged with soil. Observing the purpose of the digging—hunting insects versus consuming roots—and the shape of the mound—volcano versus fan—provides a clear distinction.
Den Builders: Groundhogs, Skunks, and Rabbits
Animals that create larger holes are typically establishing permanent residences or dens for nesting and shelter. Groundhogs, also known as woodchucks, are large burrowing rodents whose main entrance holes measure 4 to 12 inches in diameter. Their dens can extend deep and long, resulting in a large, visible mound of excavated dirt, sometimes called a “dirt porch,” at the primary entrance. Groundhogs often construct these burrows near building foundations or along hillsides, and they frequently include a concealed escape hole nearby.
Skunks are generally not digging a den when they disturb a lawn, but are instead creating numerous small, conical holes while foraging for food. These feeding pits are typically 3 to 4 inches wide and shallow, used to root out grubs and worms. The presence of these scattered, cone-shaped excavations is a strong indicator of skunk activity.
Rabbits are less adept at deep tunneling and often create shallow depressions or scrapes in the soil. These scrapes are usually hidden under dense vegetation and lined with fur and grass to serve as a temporary nest for their young. These nests are not the deep, permanent burrows characteristic of groundhogs.
Small Scale Excavators: Voles and Insects
At the smallest scale of excavation, voles and insects leave behind numerous signs that can be confused with one another. Voles are small rodents that eat roots and stems, creating coin-sized entrance holes, typically 1 to 2 inches in diameter. These openings are often obscured by mulch or vegetation.
Vole activity is distinguished by a network of visible surface runways—narrow, compressed trails of dead or clipped grass—that connect the holes. Voles use these runways to travel between their burrow and feeding areas.
Insects also contribute to yard holes, most notably the periodical cicada, which emerges after a long subterranean life cycle. As the nymphs prepare to emerge, they create perfectly round, pencil-sized holes, sometimes constructing small, earthen “chimneys” or mud caps above the surface. These emergence holes are often extremely numerous. Other insect holes include the single, clean entrances of ground-nesting bees or wasps, which are typically free of the soil mounds associated with larger mammals.