Opossums don’t build elaborate dens the way some animals do. Instead, they’re opportunists, settling into whatever sheltered spot they can find, from tree hollows and brush piles in the wild to attics and crawlspaces in neighborhoods. They’re also somewhat nomadic, frequently switching den sites rather than committing to one permanent home.
Natural Den Sites in the Wild
In forests and rural areas, opossums favor tree hollows as their primary shelter. A hollow needs to be roughly 10 centimeters (about 4 inches) or wider in diameter for an opossum to use it, though they’ll also squeeze into fissures and cracks in tree trunks. Beyond tree hollows, they readily move into abandoned burrows dug by other animals, hollow logs, rock crevices, and dense brush piles. Spaces beneath fallen trees or root systems work too.
Opossums generally prefer spots near water sources and wooded edges, where foraging is productive. They don’t dig their own burrows, so they depend entirely on existing cavities or structures. If a woodchuck or armadillo has vacated a burrow, an opossum will happily claim it.
How They Build a Nest
Once an opossum picks a den site, it gathers nesting material to line it. They collect twigs, dried leaves, grass, and whatever else is available, including discarded plastic bags and scraps of cloth in urban areas. The gathering method is distinctive: an opossum bundles materials in its mouth, passes them through its front legs, and packs them into its tail, which it curls tightly like a ring to carry everything back to the den. The resulting nest is a loose insulating pile rather than a carefully woven structure.
Common Nesting Spots Around Homes
Opossums adapt easily to suburban and urban life, and residential properties offer plenty of sheltered cavities. The most frequent locations are under porches, beneath sheds, inside crawlspaces, and in attics. Once inside an attic or crawlspace, they sometimes explore wall voids, which is when homeowners first notice scratching or movement inside the walls.
They typically gain access by climbing. Opossums are strong climbers with opposable thumbs on their hind feet, and overhanging tree branches that touch or hang near a roofline are one of the most common entry routes. From there, they look for gaps in soffits, damaged vents, holes along walls, or openings where roofing materials have shifted. Gaps around windows, doors, and fencing can also serve as entry points at ground level.
Other urban den sites include storm drains, woodpiles stacked against a house, dense shrubs, garage rafters, and the underside of decks. They don’t need much, just a cavity that’s dry, dark, and somewhat enclosed.
They Switch Dens Frequently
One of the most distinctive things about opossum denning behavior is how often they move. Opossums are semi-nomadic and regularly rotate through multiple den sites within their home range. A single opossum may use a different sleeping spot every few nights. This habit means that an opossum nesting under your porch may leave on its own within a few days, only to be replaced later by another individual passing through the area.
This nomadic pattern also means opossums don’t invest heavily in any one nest. Their dens are temporary, loosely constructed, and easily abandoned.
Nesting During Cold Weather
Opossums don’t hibernate, which makes winter denning a survival challenge, especially in northern parts of their range. Their thin ears and hairless tails are vulnerable to frostbite, so they seek out the most insulated shelter available during cold snaps. In winter, opossums tend to stay in a single den longer than they would in warmer months, venturing out less frequently to conserve energy.
They may line winter dens more thickly with leaves and other insulating material. Residential structures become especially attractive in cold weather because attics, crawlspaces, and wall voids retain heat from the building. Opossums are solitary animals and generally don’t share dens for warmth. The main exception is a mother with her young.
Where Mothers Nest With Young
Female opossums give birth after a remarkably short gestation of about 12 to 13 days. The tiny, undeveloped young crawl into the mother’s pouch and remain there for roughly 50 days, at which point their eyes and lips open and they begin leaving the pouch for short periods. They’re not fully weaned for another 30 days or so after that, and they start becoming independent at around 90 to 100 days old.
During the pouch phase, the mother’s nesting needs aren’t much different from any other opossum’s, since the young travel with her. But once the babies are large enough to leave the pouch, they ride on her back and she tends to choose more secure, enclosed den sites. Mothers with back-riding young may stay at one den longer than usual. In the wild, a female with offspring has been observed nesting at heights of around 15 meters (about 50 feet) in trees, with the male nesting separately nearby on the same tree.
Signs of an Active Opossum Den
If you suspect an opossum is nesting on your property, there are a few reliable indicators. Tracks are one of the easiest to spot: opossums leave five-toed prints on both front and hind feet, but the hind tracks are unmistakable because the opposable thumb sticks out to the side, making the print look like a small hand. Front tracks are smaller and more star-shaped.
Look for tracks near creek beds, wooded edges, along fences, or in soft soil around your home’s foundation. Opossum droppings are another sign. They’re roughly the size of a house cat’s but less uniform in shape. You may also notice a musky odor near the den entrance, scattered nesting material like leaves and shredded debris, and greasy smudge marks around entry points where the animal squeezes through repeatedly.
Keeping Opossums From Nesting on Your Property
The most effective approach is sealing entry points. Repair damaged fences, close gaps around windows and doors, cover large vents with hardware cloth, and fix any holes along exterior walls or roofing. Trim tree branches so they don’t extend within reach of your roofline, since overhanging limbs are a primary access route to attics.
Removing attractants also helps. Secure garbage cans, don’t leave pet food outside overnight, and clear brush piles or dense ground cover near your home’s foundation. Woodpiles should be stored away from the house rather than stacked against it. If an opossum is already nesting in your attic or crawlspace, it’s worth waiting a few days to see if it moves on naturally, given their habit of rotating den sites. If it stays, a one-way exclusion door over the entry point lets the animal leave but prevents re-entry.