The eastern mole is the most common mole in Iowa and the source of nearly all mole-related lawn damage across the state. These small, rarely seen mammals live almost entirely underground, digging through soil at speeds of 1 to 3 feet per minute and consuming 70 to 80 percent of their body weight in food every day. If you’re seeing raised ridges or volcano-shaped dirt mounds in your yard, you’re almost certainly dealing with this species.
What Eastern Moles Look Like
You’ll rarely see one alive, but the eastern mole (Scalopus aquaticus) is built almost entirely for underground life. They have powerful, oversized front feet shaped like paddles, a pointed snout, and velvety fur that can brush in any direction so they can move forward and backward through tunnels. Their eyes are covered by fused eyelids, leaving them able to detect only light and dark. They have no external ears but hear well through vibrations in the soil.
Adults are roughly 6 to 7 inches long, including a short, nearly hairless tail. Despite their small size, they’re remarkably efficient diggers. A single mole can extend surface tunnels at a rate of about 100 feet per day.
What Moles Eat
Moles are carnivores. About 85 percent of their diet consists of living organisms found in the soil. Earthworms are the primary food source and also their main source of water. Grubs (beetle larvae) make up the next largest share, followed by millipedes, centipedes, spiders, sow bugs, snails, and slugs. They do not eat plant roots, bulbs, or seeds, though their tunneling can uproot plants indirectly.
Their appetite is enormous relative to their size. To fuel constant digging, a mole needs to eat the equivalent of 70 to 80 percent of its body weight every single day. This relentless hunger is what drives the tunneling that tears up lawns.
When Moles Are Most Active
Moles are active year-round, but their surface tunneling peaks in spring and fall, especially after rain softens the soil and makes digging easier. These are the seasons when you’ll notice the most new ridges appearing in your lawn, sometimes overnight.
During winter cold and dry summer heat, moles retreat to deeper tunnels, typically 6 to 24 inches below the surface, where soil temperatures are more stable and prey is still available. You may not see new damage during these periods, but the moles haven’t left. They’re simply working deeper underground.
Surface Tunnels vs. Deep Tunnels
Mole burrow systems have two distinct layers. Surface runways are the raised ridges you see running through your lawn. These are feeding tunnels, dug as the mole hunts for earthworms and grubs near the soil surface. Many of these are used only once or twice and then abandoned. A few become regular travel routes used daily.
Deep runways sit 3 to 12 inches below the surface and serve as the mole’s main highway between its nest and feeding areas. You won’t see the tunnels themselves, but you’ll see evidence of them: volcano-shaped mounds of soil pushed up to the surface as the mole excavates below. Deep tunnels are often built along edges of sidewalks, driveways, fencerows, or the woody perimeter of a yard, where soil tends to hold more moisture and prey.
Mole Damage vs. Other Burrowing Animals
Iowa has several burrowing animals that leave surface evidence, and telling them apart saves you from using the wrong control strategy.
- Moles leave raised ridges (surface tunnels) and cone-shaped, volcano-like mounds with no visible entrance hole.
- Pocket gophers create crescent or fan-shaped dirt mounds with a visible plug of dirt at the tunnel entrance. Their tunnels are not visible from the surface. Unlike moles, pocket gophers are strict herbivores, so you’ll often see patches of dead vegetation between their mounds where they’ve been eating roots.
- Voles make narrow, surface-level pathways through grass, connecting small, golf ball-sized burrow openings. Their runways are flat, not raised, and they eat plants rather than insects.
If you’re seeing raised soil ridges snaking across your lawn, that’s a mole. If you’re seeing fan-shaped dirt piles with a plugged hole, that’s a gopher.
How to Control Moles in Your Yard
The good news is that mole populations are naturally low. Most yards have only one or two moles at a time, even when the damage looks extensive. A single mole can create a surprising amount of tunneling in a short period.
Trapping
Trapping is the most reliable control method. The three common trap styles are scissor-type traps (like the Victor Out-of-Sight or Mole Eliminator), in-line traps, and harpoon-style traps. All work when placed correctly.
The key is finding an active travel tunnel, not an abandoned feeding run. To test, press down a small section of a raised ridge and mark it. Check back in 24 hours. If the mole has repaired the damage, that’s an active run and a good place to set a trap. Position the trap so it straddles or sits inside the run, with a small soil obstruction that forces the mole to push through the trigger mechanism. Spring and fall are the best trapping seasons because surface activity is highest, but trapping works any time of year.
Baits
Synthetic worm-shaped baits containing a poison (sold under names like Talpirid and Tomcat) are placed directly into active tunnels. They mimic the appearance and feel of earthworms. Anecdotal reports from homeowners and extension offices have been largely positive, though rigorous independent testing is limited. When using these baits, avoid handling the worm too much or breaking it apart, as this reduces effectiveness.
Repellents
Castor oil-based repellents have shown minor effectiveness against eastern moles. In one study, a liquid castor oil product reduced mole activity in a treated area for over 30 days. For any effect at all, the product needs to be thoroughly watered into the soil: a half inch of water before application, then an inch or more after. Granular castor oil products have performed worse than liquid versions in preliminary testing. Repellents don’t kill moles. They push activity to untreated areas, which may just shift the problem to another part of your yard or your neighbor’s.
Grub Treatments
A common piece of advice is to kill lawn grubs to starve out the moles. This is largely ineffective. Grubs are only a fraction of the mole’s diet. Earthworms, which make up the majority of what moles eat, are beneficial soil organisms you don’t want to eliminate. Treating for grubs may help your lawn for other reasons, but it won’t solve a mole problem.
The Benefits Moles Provide
Moles cause real frustration, but they’re also doing useful work underground. Their tunnels create channels through compacted soil that allow air, water, and nutrients to reach plant root zones. In Iowa’s heavy clay soils, this natural aeration can improve drainage and reduce waterlogging. As they dig, moles also mix deeper subsoil with surface organic matter, redistributing nutrients and improving overall soil structure. Soil scientists sometimes call moles “accidental soil engineers.”
Their feeding also provides natural pest control. A mole actively consuming grubs, beetle larvae, and slugs is suppressing populations of insects that damage lawns and gardens. The classic brown patch caused by high grub populations is less likely in a yard where moles are feeding. Whether that tradeoff is worth the tunneling damage depends on your tolerance and how much you care about a perfectly smooth lawn.