Animal Burrow Under Your Shed? Who's Living There

A burrow entrance under your shed most likely belongs to a groundhog, skunk, rabbit, or rat, and the hole itself usually names the digger: groundhogs leave a 10–12 inch opening with a fan of excavated dirt, skunks announce themselves by smell, and rat holes are only 2–3 inches across. Before evicting anyone, check the calendar — from spring into midsummer there may be babies down there, and sealing them in creates a far worse problem than the burrow.

Most likely causes

  • Groundhog (woodchuck) — 10–12 inch entrance with a broad fan of fresh dirt outside it
  • Skunk — 6–8 inch hole, shallow den, faint musky odor around the entrance
  • Rabbit — smaller opening under the edge, more of a sheltered form than a deep tunnel
  • Rats — clean 2–3 inch holes, often several, with worn greasy runways along the shed wall
  • Opossum or stray cat — squatters using a burrow someone else dug

Compare the possible causes

Possible cause Key signs When it happens How likely
Groundhog (woodchuck) A main entrance 10–12 inches across with a conspicuous fan or apron of excavated soil, plus one or two hidden secondary exits nearby Digging peaks in spring and again in late summer; young are in the den roughly April through June Common
Skunk A 6–8 inch entrance with modest digging, a persistent faint musky smell near the hole, and small cone-shaped grub-digging holes in the lawn nearby Dens up under structures from late winter; kits are in the den May through August Common
Rabbit A smaller opening tight against the shed's edge or under a low deck lip, with clipped vegetation, pellet droppings, and tufts of fur nearby Shelter use year-round; nesting February through September Common
Rats One or several clean 2–3 inch holes along the shed base, smooth from traffic, with worn runway paths and possibly greasy rub marks along the wall Year-round, with pressure increasing in fall as outdoor food thins Less common
Opossum or stray cat An existing hole showing use — flattened grass, hairs snagged at the entrance — but no fresh digging, odor, or dirt fan Any season; opossums rotate dens and rarely stay more than a week or two Less common

Visual clues to check

  • Measure the entrance: 10–12 inches with a dirt fan says groundhog, 6–8 inches says skunk, and tight 2–3 inch holes say rats
  • Smell the area at dusk: a faint musky odor hanging around the hole is the skunk giveaway
  • Stuff the entrance loosely with wadded newspaper or leaves in the evening — pushed out by morning means the burrow is active
  • Dust a patch of flour or fine sand at the entrance overnight and read the tracks left in it the next morning
  • Scan for droppings: pea-size round pellets mean rabbit, raisin-size dark pellets mean rat, larger tubular droppings near the hole suggest skunk or opossum
  • Set a trail camera or phone camera facing the entrance for a night or two — one clear photo beats a week of guessing
  • Look at nearby damage: leveled garden vegetables point to a groundhog, cone-shaped divots all over the lawn point to a grub-hunting skunk

The causes in detail

Groundhog (woodchuck)

Groundhogs are the heavyweights of shed burrowers — a single animal moves several hundred pounds of soil creating a tunnel system that can run 20 to 30 feet with multiple entrances. The big dirt fan at the main hole is the signature; no other common yard animal throws that much soil. They're vegetarians, so expect mowed-down garden plants nearby. The real concern with a long tenancy is undermining: extensive tunneling can eventually unsettle a shed's or garage slab's footing.

Skunk

Skunks would rather borrow than dig, so they often adopt an old groundhog hole and enlarge it. Even without a spray event, an occupied skunk den gives off a low-grade musky odor you'll catch on humid evenings, and that smell is the fastest ID available. Skunks are mild-mannered and nearsighted — most 'encounters' end with the skunk waddling away — but they're also one of the primary rabies carriers in the US, so daytime activity or bold behavior deserves distance and a call to animal control.

Rabbit

Eastern cottontails don't dig extensive burrows the way European rabbits do — they mostly slip into the ready-made gap under a shed floor and rest in shallow scrapes. Round pea-size droppings and precisely clipped, angled cuts on nearby plants confirm rabbits. They're low-consequence tenants: no structural digging and no odor, though a doe may pull fur and nest in the gap, which puts the same wait-for-the-babies rule in play.

Rats

Norway rats burrow along foundations and under slabs, and their holes are dramatically smaller than a groundhog's — if you can't fit your fist in the opening, think rodent. Multiple active holes, fresh dark droppings the size of a raisin, and gnawing on the shed's corners or door bottom all point the same way. Rats near an outbuilding rarely stay there; check for bird seed, pet food, compost, or garbage that's feeding them, because removing the food source is half the fix.

Opossum or stray cat

Plenty of under-shed residents never lifted a paw to dig. Opossums are transient couch-surfers who occupy abandoned burrows briefly and move on, and neighborhood cats use the same shelter in cold snaps. Coarse white-and-gray hairs at the entrance and a trail-camera photo will sort out these squatters. For opossums, patience is a legitimate strategy — odds are good the den will be vacant within two weeks.

When to worry

  • Cracks, tilting, or sagging in the shed floor or a nearby slab — extensive groundhog tunneling can undermine footings over time
  • Any resident skunk, raccoon, or groundhog seen out at midday acting disoriented, stumbling, or unafraid — a rabies red flag; keep pets in and call animal control
  • Rat holes multiplying or runways extending from the shed toward the house foundation
  • Persistent strong skunk odor, which can mean a spray event under the floor or a dead animal in the den
  • High-pitched chittering, mewing, or squealing from under the floor in late spring — babies are present, and eviction has to wait or be handled professionally

What to do now

  1. Identify the tenant first with the newspaper test, a flour patch, or a trail camera — every next step depends on who is down there
  2. Check the calendar before evicting: most under-shed species have dependent young from about April through August, and the humane, practical move is to wait until you're sure the den is empty or babies are mobile
  3. Make the den unpleasant with humane harassment: clear cover around the entrance, leave a bright light and a portable radio playing near the hole for several days, and place ammonia-free repellent alternatives like used cat litter nearby — most animals relocate within a week
  4. Confirm everyone is out (newspaper undisturbed for 3+ nights, no tracks in the flour), then exclude: trench 10–12 inches down along the shed perimeter and bury 1/4- or 1/2-inch hardware cloth, bending the bottom outward in an L-shape a foot wide so diggers hit mesh
  5. For rats, remove the food supply — spilled bird seed, pet food, open compost, unsecured garbage — at the same time you exclude, or they'll simply dig in next door
  6. For skunks under the floor, a suspected rabid animal, or a groundhog you can't shift, call a licensed wildlife control professional; trapping and relocation is regulated or prohibited in many states

What not to do

  • Don't seal the burrow the day you find it — entombing an animal or its litter under your shed creates odor, flies, and a genuinely awful cleanup
  • Don't pour gasoline, bleach, or car exhaust into the burrow, and don't use smoke bombs under a wooden structure — dangerous, often illegal, and a fire risk
  • Don't reach into the hole or let a dog 'flush it out' — a cornered skunk sprays, and cornered anything bites
  • Don't set leg-hold traps or poison baits; both are illegal for wildlife in most states and put pets, kids, and raptors at risk
  • Don't relocate a trapped animal yourself — moving wildlife is against the law in many states, and relocated animals with hidden young leave orphans behind
  • Don't skip the buried mesh when you rebuild — blocking the hole at ground level only, without an underground barrier, gets re-dug within days

Think you know the suspect?

These animals commonly cause this clue — see their full sign profiles:

Frequently asked questions

How do I know if the burrow is still being used?

Block the entrance loosely with wadded newspaper, leaves, or a few twigs in the evening and check it the next morning for two or three nights. An active resident pushes the plug out within a night. Pair that with a patch of flour or fine sand at the opening — fresh tracks tell you not just that something's home, but what it is.

When is it safe to close up the burrow?

Only after the newspaper plug has sat undisturbed for at least three consecutive nights and you've seen no tracks — and, in spring and early summer, only after you're confident no babies remain, since kits and pups stay in the den weeks after you'd expect. If there's any doubt during baby season (roughly April through August), wait or bring in a wildlife professional with an inspection scope.

Will the animal wreck my shed's foundation?

Rabbits, skunks, and opossums won't — they use the gap without seriously excavating. Groundhogs are the exception: a multi-year burrow system can remove enough soil to unsettle a slab or pier footing, which is why a groundhog is worth evicting and excluding rather than tolerating. Check the floor for new cracks or tilt as part of your decision.

What actually works to keep animals from digging back in?

A buried barrier, and almost nothing else long-term. Trench along the shed's perimeter, attach half-inch hardware cloth to the base, run it 10–12 inches down, and bend the bottom outward into a 12-inch L-shaped shelf. Diggers go down, hit mesh, follow it outward, and give up. Repellents and radios move animals out, but only the mesh keeps the vacancy permanent.

Can I just trap it and drive it to the woods?

Please don't, even though it feels humane. Relocating wildlife is illegal or heavily restricted in many states, relocated animals frequently die in unfamiliar territory, and a mother trapped in June leaves a litter starving under your shed. Harassment-and-exclusion solves the problem at the source; where trapping is genuinely needed, a licensed wildlife control operator can do it legally.

Related yard clues

Tracks, Nests & Outdoor Clues Small Animal Tracks in Your Yard: How to Read Them Small animal tracks in your yard most often belong to rabbits, squirrels, raccoons, opossums, skunks, or a neighborhood cat or dog. Counting the toes, checking whether claw marks show, and looking at how the prints are grouped will identify the visitor faster than the shape of any single print. Read the guide → Tracks, Nests & Outdoor Clues Animal Tracks in Snow: Identify Your Winter Visitors Animal tracks in snow are most often left by rabbits, squirrels, deer, foxes, or a neighborhood cat or dog. Fresh snow is the best tracking surface your yard will ever offer, and the trail pattern — bounding sets, paired feet, heart shapes, or a dead-straight line — usually identifies the animal faster than any single print. Read the guide → Yard Holes Holes Under the Fence: What's Digging In (or Out)? A hole under a fence is usually a travel gap scraped out by rabbits, skunks, or a neighborhood dog — or the edge of a real burrow if a groundhog has moved in along the fence line. The key distinction is pass-through versus home: a shallow trench under the boards means something is commuting through your yard, while a deep hole with a big dirt pile means something is living there. Read the guide → Yard Holes Large Holes in Yard: Groundhog, Fox, Skunk, or Armadillo? A hole 6 inches across or bigger is a den entrance, and in most American yards the owner is a groundhog — an 8- to 12-inch hole with a big dirt mound is their signature. Foxes, armadillos, and skunks dig or borrow similar burrows, especially under sheds, decks, and porches, so smell, mound size, and location are what separate them. Never fill a large hole until you know it's empty. Read the guide →

Still not sure? Compare with these clues

Yard Holes Two-Inch Holes in Yard: Chipmunk, Rat, or Something Else? A round hole about two inches across is classic burrow size, and the usual suspects are chipmunks, rats, and thirteen-lined ground squirrels. Chipmunk holes are clean with no soil pile, rat holes are worn and hug structures, and ground squirrel holes sit in open, sunny lawn — those three clues sort out most cases. Read the guide → Yard Holes Holes Near Your Foundation: Causes and When to Act Holes right along a foundation usually come from chipmunks, Norway rats, or voles, all of which like the shelter a house wall provides — but water pouring from downspouts and settling backfill soil carve foundation-line holes too. Sorting burrow from washout matters, because a rat burrow against the house is the one that needs fast professional attention. Read the guide → Animal Droppings Droppings in Your Shed: Mouse, Rat, or Something Bigger? Mice are by far the most common source of droppings in a shed — look for 1/4-inch pellets with pointed ends scattered along walls, shelves, and inside boxes. Larger blunt-ended pellets suggest rats, droppings the size of a small dog's point to an opossum, and a smeared brown deposit with a chalky white cap means a snake has been hunting the rodents. Whatever you find, clean it up wet, not dry. Read the guide → Home Exterior Clues Scratching Noises in Walls at Night: What's Living in There? Scratching in your walls at night most often means mice or rats, since both are nocturnal — light, fast scratching suggests mice, while heavier gnawing and movement suggests rats. If the noise happens in daylight, especially at dawn and dusk, squirrels are the likelier tenant. The time of day, the weight of the sound, and where in the house it comes from will narrow it down before you ever see the animal. Read the guide →