The sight of fresh dirt piles disrupting a smooth lawn is a common frustration for property owners. These signs of subterranean activity are created by moles and are correctly referred to as molehills. The presence of these mounds is a definitive indicator that a mole has established a tunnel network beneath the surface. Understanding the characteristics of these dirt piles helps identify the source of the damage.
The Appearance of Molehills
Molehills possess a distinct, symmetrical shape that often resembles a miniature volcano or a cone. The dirt within these mounds is typically finely textured and uniform, pushed up from deep below the ground. This excavated soil is deposited as the mole clears debris from its deeper tunnel construction.
A defining characteristic of the molehill is the location of the tunnel entrance, which is centered at the bottom of the cone. The mole often plugs this opening with soil after depositing the excavated dirt, making the actual hole difficult to spot. This plugged, central entrance is a reliable feature for identifying a molehill over other subterranean pest mounds.
It is important to differentiate these mounds from the raised ridges that also appear on the lawn. While the mounds represent the excavation of deep, permanent tunnels, the ridges are created by the mole pushing up soil as it forages through shallow, temporary feeding tunnels. Both the conical mounds and the raised surface runs are evidence of an active mole presence.
The Purpose Behind the Mounds
Moles construct two primary types of tunnels within their territory. The shallow tunnels, which create the visible surface ridges, are used for hunting earthworms and insects near the soil surface. The deeper tunnels serve as permanent pathways for travel, nesting, and protection from predators and temperature extremes.
The mounds are “spoil piles” created when the mole excavates soil from these deeper, permanent tunnel systems. As the mole digs, it pushes the excess dirt up a vertical shaft to the surface, resulting in the characteristic conical pile. Moles constantly expand and maintain their extensive tunnel networks, which can cover up to an acre.
This continuous excavation explains why new mounds can appear frequently, sometimes overnight, as the mole clears its subterranean pathways. The location of these mounds often corresponds to areas where the mole has encountered an obstacle, such as a tree root or a foundation, forcing it to dig deeper.
Distinguishing Mole Mounds from Gopher Mounds
Differentiating between a molehill and a gopher mound is a challenge for homeowners, but the distinction is important because control methods vary significantly. The molehill, as described, is characterized by its symmetrical, volcano-like shape with dirt pushed up evenly from a central point. The entrance hole is typically obscured or plugged directly beneath the center of the pile.
In contrast, a gopher mound exhibits a distinct crescent or horseshoe shape, often described as a fan of dirt. This shape occurs because the gopher pushes the excavated soil out from the side of the tunnel entrance, rather than straight up from the center. The tunnel opening is located off to one side of the dirt pile, not in the middle.
Furthermore, the gopher’s tunnel entrance is sealed with a noticeable plug of dirt, often visible on the side of the mound. This plug protects the gopher from predators and regulates the temperature and humidity within its burrow system. The soil texture in a gopher mound can also be coarser than the fine, uniform soil found in a molehill.
Gophers are herbivores that feed on plant roots and vegetation, often pulling plants into their burrows. Moles, being insectivores, do not exhibit this behavior, focusing instead on earthworms and grubs. Observing the shape of the mound and the location of the plugged entrance are the most reliable methods for identifying the subterranean culprit.