What Do Opossums Eat? Why One in Your Yard Kills Up to 5,000 Ticks a Season

An opossum eats almost anything it can find — insects, slugs, snails, carrion, fallen fruit, garden pests, and, yes, whatever it can reach in an unsecured trash can. That last habit is the one homeowners remember. The other 95% of its diet is the reason wildlife biologists consider the opossum one of the most useful animals that can show up in a suburban yard.

The short version: opossums are opportunistic omnivores whose diet skews heavily toward insects, invertebrates, and dead animal matter — the exact things a gardener wants removed. A single opossum foraging through your mulch at night is working through slug eggs, beetle larvae, and yes, ticks, by the hundreds. Here’s what the research actually shows, section by section, plus how to tell an opossum apart from the rat it’s constantly mistaken for.

What Do Opossums Actually Eat?

Opossums are true omnivores, and their diet is dominated by animal matter rather than plants. University extension research breaks it down into four main categories: insects and invertebrates (beetles, crickets, grasshoppers, slugs, snails), carrion (already-dead animals, which opossums locate by smell and clean up), small vertebrates (mice, voles, frogs, snakes, bird eggs), and fruit (persimmons, apples, plums, blackberries, wild grapes)[1][2]. Around houses, that list expands to include pet food left outside and whatever they can reach in the trash.

Insects make up the largest single share of a wild opossum’s diet, which is the mechanism behind most of the benefits below — an animal that forages on the ground at night, eating grubs, roaches, crickets, and slugs as it goes, is functioning as a free pest-control service[3]. Diet shifts seasonally: more insects and invertebrates in summer when they’re abundant, more small mammals and stored fat reserves through the leaner winter months.

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The one-sentence takeaway: four of an opossum’s five main food groups — insects, ticks, carrion, and small rodents — are things a gardener is already trying to get rid of.

Why One Opossum Can Kill Up to 5,000 Ticks a Season

An opossum can eliminate an estimated 5,000 ticks in a single season, according to research from the Cary Institute of Ecosystem Studies[4]. The mechanism is grooming, not hunting. Opossums are fastidious self-groomers — as they forage through leaf litter and brush at night, ticks latch on the way they would to any warm-blooded animal, and the opossum grooms them off and swallows them before they can attach and feed.

Ecologist Richard Ostfeld and colleagues at the Cary Institute tested this directly: they caged six wildlife species — white-footed mice, chipmunks, squirrels, opossums, veerys, and catbirds — and exposed each to 100 ticks, then counted how many were still attached and feeding afterward. Opossums groomed away and consumed more than 90% of the ticks that landed on them, making them the most efficient tick-killers of the six species tested — Ostfeld reported he “had no suspicion they’d be such efficient tick-killing animals” going into the study[4]. The 5,000-tick figure is an extrapolation from that per-animal kill rate across a season of nightly foraging, not a direct field count — but it’s the number wildlife agencies and Lyme-disease researchers cite when explaining why opossums matter for tick control.

White-footed mice, by contrast, are effective tick hosts — they groom poorly and are a primary reservoir for the Lyme-causing bacterium. An opossum in the yard doesn’t just remove ticks directly; it may also be denting the local mouse population through predation, indirectly limiting the tick life cycle at both ends.

What About the Trash Cans? Separating Reputation From Reality

The trash-can habit is real, not an urban myth. Opossums have an excellent sense of smell, and an unsecured garbage can or an outdoor pet food bowl is one of the strongest attractants in a residential yard[5]. Once an opossum learns a can is an easy meal, it will keep coming back — that’s the honest version of the reputation, and pretending otherwise doesn’t help anyone manage it.

What changes the calculation is scale and intent. A raccoon methodically works a latch open. An opossum is an opportunist without much dexterity or persistence — it exploits an already-open or unsecured can rather than defeating a secure one. University IPM guidance frames the fix as entirely preventive, not eradication-based: use garbage cans with tight-fitting, locking lids; bring pet food in by nightfall; and pick up fallen fruit regularly so there’s nothing drawing them to the property line in the first place[5]. No opossum-specific chemical repellents are registered with the EPA, so exclusion and food-source removal are the only tools that actually work — anything sold as an opossum repellent spray is unproven[2].

Do Opossums Dig Up Your Garden or Lawn?

Rarely, and not the way raccoons or skunks do. Opossums are built for climbing, not digging — their claws and forelimbs aren’t strong enough to tear up turf hunting for grubs the way a raccoon’s are, and university extension guidance is explicit that opossums do not cause turfgrass damage the way raccoons do[2]. If you’re finding torn-up patches of lawn or small excavated holes, the more likely culprits are raccoons, skunks, or ground squirrels — not an opossum passing through.

This is a genuinely useful diagnostic when you’re trying to identify what’s visiting your yard at night: an opossum will leave latrine sites (concentrated droppings in one spot) and knocked-over items it was climbing on, but not the divot-pocked lawn associated with grub-hunting mammals.

Opossum vs. Rat: How to Tell Them Apart

Opossums are marsupials, not rodents — they’re more closely related to kangaroos than to rats — but their pointed face and long, hairless tail lead a lot of people to assume they’re an oversized rat, which usually triggers the wrong response[2]. Rat-control measures like poison bait or snap traps are the wrong tool for an opossum and, because opossums are protected or regulated in many states, can also be the wrong legal move.

Biggest single tell: the teeth and the gait. Fifty visible teeth in a wide-open defensive hiss and a slow, deliberate waddle rule out a rat immediately — rats are fast, twitchy, and don’t display anywhere near that much dentition.

Why Opossums Almost Never Carry Rabies

Opossums can technically contract rabies, but confirmed cases are rare, and the reason is physiological rather than behavioral. An opossum’s body temperature runs cooler than most placental mammals — roughly 94-97°F, compared to 97-103°F in animals like raccoons, skunks, and dogs[6]. The rabies virus is temperature-sensitive; it struggles to replicate fast enough to establish infection in a host running that cool, so most exposures don’t progress to symptomatic disease. This doesn’t mean an opossum can’t carry other pathogens — leptospirosis and fleas are more realistic concerns — but rabies specifically is a low-probability outcome even after a bite or scratch, which matters when deciding whether an opossum encounter is an emergency.

The Opossum’s Other Superpower: Snake Venom Immunity

Opossums also eat venomous snakes, and they can do it because their blood contains proteins that neutralize snake venom[3]. Researchers at San Jose State University isolated the specific peptide responsible — an 11-amino-acid chain from opossum serum — and showed it neutralizes venom from both the Western Diamondback rattlesnake and India’s Russell’s viper. In mouse trials, untreated animals died from venom exposure within 12 hours; animals treated with the opossum-derived peptide showed no ill effects at all[7]. Because the peptide can be manufactured cheaply using engineered bacteria rather than harvested from horse serum (the traditional antivenom source), researchers see it as a candidate for low-cost antivenom in regions with high snakebite mortality. It’s an unusually direct line from “what’s eating my garden pests at night” to active pharmaceutical research.

Should You Attract Opossums to Your Garden — or Move Them Along?

For most gardeners, the honest answer is: leave them alone and secure your trash. An opossum passing through is providing tick, slug, and rodent control at no cost and doing negligible structural damage — the trade-off is fundamentally different from a rabbit or squirrel problem, where the animal is directly eating your plants or bulbs rather than the pests attacking them. If rabbits are the issue, the fix is exclusion and repellents around the beds themselves — see our guide on how to keep rabbits out of your garden naturally. If squirrels are digging up bulbs or raiding fruit trees, the approach is similarly targeted — covered in our guide to squirrel-proofing your garden. An opossum doesn’t need that kind of active deterrence unless it’s specifically denning under a structure or repeatedly raiding a food source, in which case the fix is exclusion (seal gaps 3 inches or wider) and removing the attractant, not trapping or poisoning.

The one scenario worth acting on: an opossum that’s active during full daylight, moving erratically, or showing no fear of people. That’s atypical behavior for a strictly nocturnal species and is worth a call to a local wildlife rehabilitator rather than a wait-and-see approach — not because it’s likely rabid (it almost certainly isn’t, for the reasons above), but because daytime activity in an otherwise nocturnal animal usually signals illness, injury, or a mother pushed out of her den.

One thing not to do: deliberately set out food to keep an opossum around. It sounds like the natural extension of wanting more tick control, but it works against you. A fed opossum stops ranging as widely for insects and carrion — the exact behavior that makes it useful — and instead camps near the free meal, which increases the odds it dens under your porch or shed rather than passing through. Let it forage on its own schedule; the pest control comes from the ranging, not from the animal’s mere presence in the yard.

Frequently Asked Questions

What do opossums eat the most of?

Insects and other invertebrates make up the largest share of a wild opossum’s diet, followed by carrion, small vertebrates like mice and voles, and fruit. Around homes, that shifts to include pet food and garbage when it’s accessible[1].

Do opossums eat cats or small dogs?

No. Opossums aren’t predators of animals their own size or larger; they’re non-aggressive and rely on playing dead rather than attacking. They may compete with outdoor pets for food left in a bowl, but they don’t target cats or dogs.

Do opossums really eat 5,000 ticks a season?

That figure is a research-based estimate from Cary Institute studies on tick-grooming efficiency, not a directly observed field count — but the underlying finding, that opossums groom off and consume more than 90% of ticks that land on them, is measured, peer-reviewed research[4].

Should I be worried about an opossum in my yard?

Generally no. A nocturnal opossum that leaves at dawn is functioning as pest control. Only daytime activity, erratic movement, or denning under a porch or shed warrants a closer look or a call to a wildlife rehabilitator.

Are opossums rodents?

No. Opossums are marsupials — North America’s only native marsupial — and are more closely related to kangaroos than to rats or mice, despite the superficial resemblance[2].

Sources

1. Alabama Cooperative Extension System. Virginia Opossum: Our Only Native Marsupial.
2. University of Nebraska–Lincoln Extension. Opossums (Publication G1688).
3. University of Illinois College of Veterinary Medicine. Why Should I Care About Virginia Opossums?
4. Cary Institute of Ecosystem Studies. Opossums — Killers of Ticks.
5. UC Statewide Integrated Pest Management Program. Opossum — Home and Landscape.
6. Cornell Wildlife Health Lab. Weird & Wonderful Wildlife — The Opossum.
7. ScienceDaily. Opossum-Based Antidote to Venom From Snake Bites Could Save Thousands of Lives.
8. Internet Center for Wildlife Damage Management. Opossums.
9. Illinois Department of Public Health. Norway Rats.