Digging a proper burrow is genuinely expensive work: it costs an animal time, energy, and exposure to predators while the entrances are unfinished and unfamiliar. A meaningful share of backyard wildlife solves that cost by simply not doing the digging at all, moving into a tunnel system another species already built and then abandoned, sometimes years earlier. Groundhog burrows in particular function as a kind of shared suburban infrastructure, reused by a rotating cast of species long after the groundhog that dug them has moved on or died.
Why Groundhog Burrows Are the Most Reused
Groundhogs build unusually elaborate burrow systems for a mid-sized suburban mammal, often with a main entrance plus several secondary "plunge holes" used only for quick escape, connected by tunnels that can run ten feet or more below the surface. That scale of engineering, described in more detail in our groundhog burrow piece, is far more than most other species would build for themselves, which makes an abandoned groundhog den an unusually good deal for the next occupant: a ready-made, multi-exit shelter requiring only minor upkeep.
Who Moves In
- Cottontail rabbits — frequently raise litters in the outer chambers of abandoned groundhog burrows rather than digging their own natal burrows from scratch
- Striped skunks — readily take over vacant burrows, sometimes enlarging an entrance slightly but rarely doing significant new digging
- Virginia opossums — den opportunistically in abandoned burrows for weeks at a time, one of several den types opossums rotate through rather than a single permanent home
- Red foxes — commonly convert an old groundhog burrow into a natal den each spring by widening the entrance and clearing the main tunnel
- Snakes and cavity-nesting insects — use abandoned tunnel sections for overwintering shelter, a use that leaves the burrow structure itself essentially untouched
Burrow reuse is not always one species moving in after another leaves. Cases of active groundhog burrows with a cohabiting rabbit or opossum denning in a side chamber, at a safe distance from the groundhog itself, have been documented, since none of the species involved is territorial enough underground to actively evict a quiet neighbor using a different section of tunnel.
A Similar Pattern Further South
The same commensal pattern shows up even more dramatically outside the opossum's core range: gopher tortoise burrows in the sandy soils of the southeastern coastal plain are used by well over a hundred other species documented over the years, from indigo snakes and gopher frogs to burrowing owls, making the tortoise a textbook example of what ecologists call a keystone excavator. Suburban groundhog burrows in wooded and mixed-use areas further north function on a smaller scale but along the same basic principle: one species' excavation effort becomes shared infrastructure for a whole community of animals that would otherwise have to dig for themselves or go without reliable underground shelter.
Why This Matters for Yard Management
Filling in or collapsing what looks like an inactive burrow can displace far more than the original digger; a burrow abandoned by its groundhog builder years ago may currently house a nesting rabbit, a denning skunk, or a fox raising kits, none of which are visible from the entrance alone. Watching an entrance for several consecutive evenings, looking for fresh digging, tracks, or droppings, is a more reliable way to judge current occupancy than assuming a lack of an obvious groundhog sighting means the burrow is empty.
The Internet Center for Wildlife Damage Management, a resource maintained by university extension wildlife specialists, specifically recommends confirming vacancy before any burrow exclusion or fill-in work, precisely because of how often a different species than the one originally suspected turns out to be using the tunnel.
Signs a Burrow Is Currently Occupied
- Fresh soil at the entrance — loose, uncompacted dirt without leaf litter or cobwebs across the opening
- A worn path leading to the entrance — regular travel packs down vegetation into a visible trail
- Fresh droppings or tracks nearby — the clearest confirmation of an active resident, though not which species without closer inspection
- Multiple entrances with only some showing activity — consistent with a species using only part of a larger, older burrow system
The groundhog that dug a burrow five years ago may be long gone, but the tunnel it left behind is likely still doing shelter duty for something.
A yard with an old, disused-looking burrow is rarely as empty as it appears; treating any burrow as potentially occupied, regardless of which species dug it originally, is the safer default before any yard work disturbs it.