A mole hill is a common sight in lawns and gardens, representing the underground activity of a specialized mammal. These formations are mounds of earth pushed to the surface as a result of a mole constructing or maintaining its subsurface tunnel network. The appearance of these hills is the most visible sign that a mole is actively working beneath the turf.
Anatomy and Purpose of a Mole Hill
A mole hill is characterized by its distinct conical or volcano-like shape, appearing as a small dome of soil. This structure is composed of fine, loose earth excavated by the mole during tunneling. These hills are typically between 6 and 24 inches in diameter and a few inches high, formed when soil is pushed up a vertical shaft connecting the deep tunnel system to the surface.
The primary purpose of the mole hill is to serve as an exhaust vent for displaced soil, making it a disposal site, not the main entrance to the tunnel network. As the mole digs, it uses its powerful forelimbs to shear soil and push the loose material upward. This process results in the characteristic mound, indicating active burrow construction or repair.
The Mole Responsible
The animal behind the mole hill belongs to the family Talpidae. These creatures possess remarkable physical adaptations for their subterranean life, including short, powerful forelimbs rotated outward like oars. Their large, paddle-like front paws are equipped with broad claws, making them highly efficient excavators. Moles also have dense, velvety fur that prevents soil from becoming trapped, allowing them to move easily through tight tunnels.
Moles are driven to dig primarily to create feeding tunnels in their continuous search for prey. They are insectivores, and their diet consists mainly of earthworms, insect larvae, and other small invertebrates found in the soil. The tunnels act as traps; the mole senses when prey falls in and rushes to catch it. Moles are mostly solitary, meaning one animal can be responsible for an extensive network of tunnels and multiple hills.
Differentiating Mole Hills from Similar Mounds
Mole hills can sometimes be confused with mounds created by other burrowing pests, most notably pocket gophers. Mole hills are characteristically conical or volcano-shaped, with loose soil pushed up through a central opening that is often difficult to spot. The soil tends to be fine and uniformly textured, representing material excavated from the deeper underground system.
In contrast, pocket gophers create mounds that are distinctly crescent or fan-shaped. Gopher mounds usually have a visible plug of soil off to one side, sealing the main tunnel entrance. The soil in a gopher mound is often coarser and may include plant matter, reflecting their herbivorous diet and shallower tunneling activity. Other disturbances, such as those from voles or ants, do not produce the large, conical mounds that signify a mole’s presence.