Moles are burrowing mammals whose presence is often announced by unsightly mounds and raised ridges in a lawn or garden. The common assumption is that these subterranean creatures are responsible for consuming garden plants and roots. However, moles do not eat garden plants; they are insectivores, meaning the damage observed is indirect, a consequence of their tunneling lifestyle. Understanding this distinction is the first step in correctly identifying the source of plant death and applying the right control methods.
The Truth About Mole Diets
Moles are classified as insectivores, meaning they hunt and consume small animals rather than vegetation. Their diet primarily consists of earthworms, which often make up the majority of their food intake, and insect larvae (grubs). They also eat other soil-dwelling invertebrates, including beetles, ants, spiders, and centipedes that fall into their tunnel systems.
Moles possess an incredibly high metabolism, necessitating a constant and substantial intake of food; a single mole can consume up to 100% of its own body weight in prey daily. This ravenous appetite drives their extensive tunneling activity as they constantly patrol their networks searching for their next meal. They use a specialized toxin in their saliva to paralyze earthworms, allowing them to store live prey in underground chambers for later consumption.
Why Garden Plants Still Suffer
Even though moles do not eat plants, their tunneling activities inflict substantial collateral damage, leading to the death or wilting of garden vegetation. Tunnels are typically dug just below the surface, creating raised ridges that directly sever the delicate root systems of plants and turf. This separation prevents the plant from absorbing necessary water and nutrients, causing it to fail.
The creation of these underground voids also introduces significant air pockets around the remaining roots. When roots are exposed to these empty spaces, they quickly dry out (desiccation), causing the plant to wilt and die even if the roots were not completely severed. This disturbance weakens the overall soil structure, making it less stable and more prone to erosion.
Soil Upheaval
The act of a mole pushing up volcano-shaped molehills brings deeper soil to the surface, disrupting the stratification necessary for healthy root growth. This constant upheaval makes it difficult for new plants to establish a firm hold and for established plants to maintain stability.
The Real Plant Eaters
The destruction of roots, bulbs, and entire plants is most often the work of voles, small rodents frequently mistaken for moles due to their similar subterranean habits. Voles are herbivores whose diet consists of plant materials, including grass, roots, tubers, bulbs, and the bark of young trees and shrubs. They are the true culprits behind a garden that has had its vegetation cleanly consumed.
Voles often use the existing tunnel systems created by moles as highways to travel undetected to plant roots. This cohabitation often leads to the misidentification of the pest, as the mole’s visible mounds are present while the vole is doing the actual damage.
Telling the two apart is possible by examining the evidence they leave behind. Moles create conical, volcano-shaped mounds of dirt and raised ridges just below the surface as they hunt. Voles, conversely, leave small, visible, golf-ball-sized entrance holes and create distinct, narrow runways on the surface of the lawn where they clip the grass down. If plants are cleanly chewed or bulbs are gone, a vole is responsible.