Moles do not hibernate and remain active throughout winter. Unlike many burrowing mammals that enter a prolonged dormant state when temperatures drop, moles keep tunneling and feeding year-round, driven by a metabolism so demanding that they need to eat roughly half their body weight in invertebrates every day just to survive. What changes in winter is not whether moles are active but where and how they work. Their tunnels shift deeper underground, their digging patterns change, and the signs they leave on your lawn look different from the familiar summer molehills. Understanding those differences is the key to spotting winter mole activity and deciding whether to act on it.
Why Moles Cannot Afford to Stop
A mole’s body is essentially a digging machine running at full throttle. Pushing through soil requires enormous energy, and moles have evolved a metabolic rate to match. They eat earthworms, beetle larvae, and other soil invertebrates almost constantly, cycling through periods of activity and rest roughly every four hours around the clock. Going without food for even 12 to 24 hours can kill them. Hibernation, which requires animals to build up fat reserves and slow their metabolism to a crawl, simply is not an option for an animal with this kind of energy demand.
Some related subterranean mammals have evolved ways to reduce energy expenditure in cold conditions. Cape golden moles, for instance, can enter brief torpor when ambient temperatures plunge, dropping their metabolic rate dramatically to ride out short cold spells. Hottentot golden moles, studied at high altitude in southern Africa, forage throughout the year but appear to restrict winter activity to shorter, more intense bouts rather than the longer foraging sessions seen in warmer months.1PubMed. Seasonal energetics of the Hottentot golden mole at 1500 m altitude True moles in North America and Europe take a different approach: they stay active at roughly the same overall intensity but shift their operations underground where conditions are more stable.
The Deeper Dig in Cold Weather
The most important change in winter mole behavior is depth. During spring and summer, moles create those frustrating shallow surface tunnels just below the turf, where earthworms and grubs are plentiful in the warm, moist topsoil. When frost arrives, soil invertebrates respond by migrating downward. Earthworms in temperate climates avoid frozen soil by burrowing into deeper layers where the temperature stays above freezing.2Pedobiologia. Overwintering adaptations in earthworms Moles simply follow their food supply.
Classic field studies in British woodlands found that little new surface-level digging occurs for much of the year, with one exception: winter, when frost pushes soil fauna deeper and forces moles to excavate new, deeper tunnels to reach them.3Journal of Zoology. Mole activity in woodlands, fens and other habitats This is somewhat counterintuitive. Many homeowners assume the absence of fresh surface tunnels in December means the moles have left or gone dormant. In reality, the moles are working just as hard, only further from the surface where you cannot see the evidence as easily.
The depth shift also means that when moles do push soil upward in winter, the result tends to be molehills rather than the long, raised ridges of shallow feeding tunnels. The mole is excavating deep runs and needs somewhere to dump the displaced earth, so it pushes it vertically to the surface in cone-shaped mounds. If you see fresh molehills appearing on your lawn in January but no raised ridges, that pattern is characteristic of winter digging.
How to Spot Winter Mole Activity
Telling whether your moles are still at work during cold months takes a slightly different eye than in summer. Here are the signs to look for:
- Fresh molehills: These are the most reliable winter indicator. A new molehill will have loose, crumbly soil that looks darker and moister than the surrounding earth. If you flatten a molehill and it reappears within a day or two, the tunnel beneath it is actively being used.
- Soft or sinking patches: Even when surface ridges are not visible, deep tunnels can cause the ground above to feel spongy or settle slightly. Walk your yard after a thaw and note any areas where the turf gives unexpectedly underfoot.
- Raised ridges after warm spells: During mild winter stretches, earthworms move back toward the surface temporarily, and moles follow. You may see a brief return of shallow feeding tunnels during a thaw, only for them to disappear again when the cold returns.
- No plant damage: Moles eat invertebrates, not roots or bulbs. If you see chewed roots or missing bulbs, the culprit is more likely a vole, which often uses mole tunnels as ready-made highways. This misidentification is one of the most common mistakes homeowners make.
The mole-versus-vole distinction matters because the two animals require completely different control strategies. Voles are rodents that eat plant material, while moles are insectivores that ignore your garden plants entirely. The damage moles cause is structural: disrupted root systems from tunneling, uneven ground, and cosmetic lawn damage from molehills. If your tulip bulbs are disappearing in winter, blame the vole, not the mole.
Other Animals in the Tunnel Network
Mole tunnels serve as underground infrastructure for a surprising number of other small mammals, and this use intensifies in winter. A study of short-tailed shrews found that these animals used mole tunnels significantly more often during winter than during spring, with a lower proportion of aboveground captures in cold months.4BioOne Complete (The American Midland Naturalist). Seasonal Differences in the Use of Mole Tunnels by Short-tailed Shrews Blarina carolinensis The reason is straightforward: subterranean temperatures vary far less than those at the surface, making tunnels a comparatively warm refuge when the ground above is frozen or snow-covered.
Voles, mice, and shrews all exploit mole tunnels opportunistically. This means that even if your moles are digging less visibly in winter, their tunnel system continues to see heavy traffic from other species. If you are finding gnawed roots or bark damage at the base of shrubs, the animals responsible likely entered through mole-built corridors. Addressing mole tunnels in winter can sometimes reduce damage caused by these secondary occupants as well.
What to Do About Winter Moles
Whether you should act against moles in winter depends on how much damage they are causing and how realistic your expectations are. Winter is actually a strategically interesting time for control because mole behavior becomes more predictable. With fewer shallow feeding tunnels and more reliance on deep permanent runs, you can focus your efforts on the tunnels the moles are actually using rather than chasing dozens of surface-level pathways that may have been used once and abandoned.
The first step is finding the active deep runs. Look for the main travel tunnels rather than the branching feeding tunnels. Main runs tend to follow linear features like fence lines, garden borders, sidewalk edges, or the perimeter of buildings. To confirm a tunnel is active, press down a small section with your foot and mark it. If the tunnel is repaired within 24 to 48 hours, it is an active run and a good target.
Common control approaches include:
- Trapping: This remains the most consistently effective method. Scissor-jaw and harpoon-style traps placed in confirmed active runs can catch moles year-round. Winter trapping can be more efficient than summer trapping because you are working with fewer, more predictable active tunnels.
- Baits: Commercially available mole baits shaped to miitate earthworms or grubs are placed directly in active tunnels. Results are mixed; some pest professionals consider them less reliable than traps because moles may push the bait aside rather than eat it.
- Reducing food supply: Treating your lawn for grubs with products aimed at Japanese beetle larvae or European chafer can reduce one food source, but earthworms typically make up the bulk of a mole’s diet, and you cannot realistically eliminate earthworms from your soil. This strategy reduces surface-level grub-seeking tunnels more than deep winter tunneling.
- Waiting it out: If the winter damage is mostly cosmetic molehills on a dormant lawn, some homeowners prefer to flatten the hills periodically and address the moles in spring when trapping conditions are easier and surface tunnel patterns are more visible.
Products marketed as mole repellents, such as castor oil granules, ultrasonic stakes, or windmill vibration devices, have little peer-reviewed evidence behind them. Many pest management extension services are blunt about this: most repellents do not reliably drive moles out of an established territory. They may shift activity temporarily from one part of the yard to another, but the moles tend to come back once they habituate to the stimulus.
Winter and the Mole’s Shrinking Skull
One of the more remarkable biological findings about moles in recent years involves what happens to their skulls across seasons. European moles exhibit a phenomenon where their skulls physically shrink heading into winter, reaching minimum size around November of their first year, then partially regrowing by the following summer. Research on the closely related American shrew-mole found a parallel pattern: individuals shrank their relative skull size by about 11 percent, with a partial regrowth of roughly 4 percent the next spring.5PubMed Central. Winter conditions, not resource availability alone, may drive reversible seasonal skull size changes in moles
This phenomenon, sometimes called Dehnel’s phenomenon after the zoologist who first described it in shrews, was long thought to be driven purely by food scarcity. If resources are scarce, the theory went, a smaller brain and skull require less energy to maintain. But the study on shrew-moles complicates that idea. The skull shrinkage occurred during winter when the local summer, not winter, was actually the harshest period for food availability. The researchers suggested that winter conditions themselves, possibly temperature or photoperiod, may drive the size change independently of resource stress. The skull of a mole in your December yard is measurably smaller than the same animal’s skull in July, even as the mole remains fully active and feeding.
Frozen Ground and the Limits of Digging
There is a practical limit to how cold it can get before even a mole struggles. In areas with severe winters and deep frost lines, the top several inches or even feet of soil can freeze solid, becoming essentially impenetrable. Moles deal with this by retreating to tunnels below the frost line, where the soil remains workable. In most of the temperate United States and Europe, the frost line sits somewhere between a few inches and a few feet deep, depending on latitude, soil type, and snow cover. Snow actually helps moles by insulating the ground and preventing the frost from penetrating as deeply.
Sandy or well-drained soils freeze more quickly and deeply than heavy clay soils, so mole activity in sandy-soil regions may become less visible in winter than in areas with denser, moisture-retaining soils. If your area experiences prolonged hard freezes with no snow cover, you may see almost no mole sign at the surface for weeks, only for activity to resume quickly once the thaw begins. The moles have not left; they are simply operating below the frozen layer, in a zone you are unlikely to see evidence of from above.
This underground thermal buffering also explains why subterranean life generally remains viable even in harsh winters. The temperature a foot or two below the surface holds relatively steady compared to the wild swings at the surface, providing moles and their prey with a livable environment even when the air above is well below freezing. It is this thermal stability that makes the underground world such an effective year-round habitat, and why moles never needed to evolve hibernation in the first place.
Spring Cleanup After a Winter of Mole Activity
Even if you choose not to intervene during the winter months, there are practical steps worth taking once the ground thaws and you can assess the full extent of the damage. Molehills left over the winter will have killed the grass beneath them, leaving bare patches. Rake those mounds flat as early as possible in spring, spread a thin layer of topsoil if needed, and reseed. The sooner you do this, the better chance the grass has of filling in before weeds colonize the bare spots.
For tunnel damage, rolling your lawn with a water-filled roller in early spring can press the displaced sod back into contact with the soil beneath it, encouraging the turf roots to re-establish. This is more effective on shallow tunnel damage than on deep runs, where the voids are too far underground for surface rolling to reach. Areas that remain persistently spongy may need more soil added and reseeding.
Spring is also the best time to set traps if your goal is to reduce the mole population before the breeding season. Moles breed in late winter to early spring in most temperate regions, with a single litter of three to five pups arriving around four to six weeks later. Catching a mole before it breeds can prevent a whole season’s worth of new tunnel excavation. The burst of shallow tunneling that comes in March and April, as earthworms move back toward the surface and moles follow, makes active runs easier to identify and trap than at any other time of year.