Pest Control
How to Get Rid of Opossum Invaders in Your Yard and Attic
Opossum vs. Raccoon: Confirming the Intruder
Before deploying deterrents, verify the species. Homeowners frequently misidentify opossum (*Didelphis virginiana*) damage as raccoon activity, leading to ineffective control measures. Opossums lack the dexterous front paws required to unlatch garbage cans or tear heavy asphalt shingles. Instead, they rely on their 50 sharp teeth to rip through flexible vinyl vent covers, chew through rotten fascia boards, and knock over unsecured trash bins.
Damage Identification Matrix
| Indicator | Opossum Sign | Raccoon Sign |
|---|---|---|
| Trash Cans | Knocked over, scattered debris | Lids removed, contents selectively eaten |
| Feces | Scattered randomly along pathways | Communal latrines in elevated, flat areas |
| Entry Points | Torn flexible vents, rotting wood gaps | Torn shingles, chewed thick wood/metal |
| Noise | Hissing, clicking, low growls | Heavy thumping, chittering, vocal cries |
Perimeter Exclusion: Fencing and Habitat Modification
Opossums are poor climbers compared to squirrels or raccoons, but they are relentless diggers. Standard chicken wire is useless; their teeth and claws easily compromise thin-gauge poultry netting. To secure your yard, garden, or under-deck crawlspaces, you must install a physical digging barrier.
The L-Footer Trench Method
- Dig a Trench: Excavate a 12-inch deep, 6-inch wide trench along the perimeter of your deck, shed, or garden bed.
- Select the Right Mesh: Purchase 19-gauge, 1/2-inch galvanized hardware cloth. Do not use 20-gauge or larger mesh sizes.
- Form the 'L': Bend the hardware cloth into an L-shape. The vertical leg should be 24 inches high, and the horizontal leg should be 12 inches wide.
- Install and Bury: Place the cloth in the trench so the horizontal leg points away from the protected area (outward). When the opossum digs at the base of the fence, it encounters the buried wire and cannot proceed.
- Backfill: Cover the horizontal leg with soil and mulch. Secure the vertical leg to your existing structure using heavy-duty galvanized staples.
Deterrent Efficacy: What Works and What Fails
The pest control market is saturated with repellents that offer negligible results against marsupials. Opossums have a highly developed olfactory system and are notoriously unfazed by ultrasonic frequencies or mild scent deterrents. Below is an evidence-based evaluation of common deterrents.
| Deterrent Type | Specific Product/Method | Efficacy | Cost Range |
|---|---|---|---|
| Motion-Activated Sprinklers | Orbit 62100 Yard Enforcer | High. Sudden water bursts exploit their startle response. | $70 - $90 |
| Lighting | Motion-activated LED floodlights (3000+ lumens) | Moderate. Works initially, but habituation occurs within 2 weeks. | $40 - $60 |
| Scent Repellents | Predator urine (coyote/fox) | Low. Washes away in rain; urban opossums ignore it. | $15 - $25 |
| Ultrasonic Emitters | Various plug-in yard repellers | None. Opossums lack the auditory sensitivity to be deterred. | $20 - $40 |
| Ammonia/Chemicals | Soaked rags in coffee cans | Hazardous. Illegal in many states; toxic to pets and soil. | N/A |
Expert Tip: The Orbit Yard Enforcer is most effective when placed near known foraging routes (e.g., beside pet food bowls or compost bins). Set the sensor height to 8 inches off the ground to specifically target opossums while ignoring neighborhood cats.
Attic and Crawlspace Eviction Tactics
If an opossum has established a den in your attic or crawlspace, sealing the entry point while the animal is inside will result in severe structural damage as it attempts to escape, alongside the odor of a decaying carcass if it starves. You must evict the animal first.
One-Way Exclusion Doors
Install a one-way exclusion door over the primary entry point. These devices allow the animal to exit but physically block re-entry. Leave the door in place for a minimum of 5 to 7 consecutive days. Monitor the exit point with a trail camera to confirm the animal has vacated.
CRITICAL WARNING: Pup Season (March through August)
According to the Humane Society of the United States, female opossums carry litters of up to 8 young in their pouches for two months, and the young ride on their backs for another two months. Never use one-way doors or traps during spring and summer without confirming the mother is not separated from her dependent young, which will result in orphaned animals dying inside your walls.
Live Trapping: Specifications, Bait, and Legal Constraints
When exclusion and deterrents fail, live trapping is the final resort. However, trapping is heavily regulated due to the opossum's status as a potential rabies vector species, despite their naturally low body temperature (94°F-97°F) making them highly resistant to the rabies virus.
Trap Selection and Baiting
- Trap Dimensions: Use a 10" x 12" x 32" galvanized steel cage trap (e.g., Havahart Model 1089 or Tru-Catch 36D). Smaller traps will catch squirrels or skunks; larger traps may allow the opossum to turn around and escape the trigger mechanism.
- Optimal Bait: Canned sardines in oil, wet pungent cat food, or marshmallows. Do not use peanut butter or apples, as these attract non-target skunks and raccoons.
- Placement: Set the trap against a wall or fence line in the evening. Opossums are thigmotactic, meaning they prefer to travel with their flanks touching solid objects.
- Protection: Cover the top half of the trap with a dark towel to reduce stress and prevent the animal from thrashing and damaging its snout against the wire.
The Legal Reality of Relocation
Before setting a trap, consult your state's Department of Natural Resources (DNR) or Fish and Wildlife regulations. According to data compiled by the Internet Center for Wildlife Damage Management, many states (including California, New York, and Massachusetts) strictly prohibit the relocation of trapped wildlife. In these jurisdictions, a trapped opossum must either be released on the exact property where it was captured (which often fails to solve the problem) or humanely euthanized by a licensed Nuisance Wildlife Control Operator (NWCO). Relocating an opossum to a new environment typically results in the animal's death within 48 hours due to territorial disputes with established wildlife and lack of known food/water sources.
Cost Expectation: Hiring a licensed NWCO for professional trapping, exclusion, and sanitization typically costs between $250 and $600, depending on the complexity of the entry points and local disposal regulations.
The Ecological Case for Tolerance
If the opossum is merely passing through your yard and not causing structural damage, consider tolerating its presence. As noted by Penn State Extension, opossums are highly beneficial to suburban ecosystems. A single opossum can consume up to 5,000 ticks in a single season, significantly reducing the localized risk of Lyme disease. Furthermore, they are immune to most snake venoms and actively hunt rodents, providing natural, chemical-free pest control for your property.
Frequently Asked Questions
Will an opossum attack my dog or cat?
No. Opossums are non-aggressive and prefer to flee or 'play dead' (a comatose state triggered by extreme stress) when confronted by pets. While they may bare their 50 teeth and hiss defensively, they will rarely initiate an attack unless physically cornered or handled.
How do I clean up opossum droppings in my crawlspace?
Unlike raccoon feces, which carry the dangerous *Baylisascaris* roundworm, opossum feces do not pose a severe zoonotic threat to humans. However, you should still wear an N95 respirator and nitrile gloves. Mist the droppings with a 10% bleach solution to suppress dust, scoop them into a heavy-duty contractor bag, and dispose of them in your exterior trash.
Do mothballs work to keep opossums out of my shed?
Mothballs are entirely ineffective for outdoor or semi-outdoor opossum deterrence. Furthermore, using mothballs in a manner inconsistent with their EPA-approved labeling (such as scattering them in yards or sheds) is a violation of federal pesticide law and poses severe toxicity risks to children, pets, and local groundwater.
