The phrase “playing possum” is a common idiom meaning to pretend to be asleep or dead to trick someone. It implies a conscious choice—a clever ruse. However, for the Virginia Opossum (Didelphis virginiana), this famous defense mechanism is anything but an act. It is a completely involuntary physiological response to terror.

When an opossum is overwhelmed by a threat—such as being cornered by a dog or confronted by a predator—its brain overloads. It enters a state of catatonia or tonic immobility. It is essentially fainting from fear.

The Biology of “Playing Dead”

This isn’t just lying down and closing eyes. The opossum undergoes a profound physical transformation designed to convince a predator that it is not just dead, but long dead and unappetizing.

The Physical Signs:

• Collapse: The body goes limp and curls onto its side.
• Rigidity: The muscles may stiffen, making the animal feel like rigor mortis has set in.
• Breathing: Respiration slows down significantly, becoming almost imperceptible.
• The Stare: The eyes remain open and fixed in a glassy stare.
• The Tongue: The tongue lolls out of the side of the mouth, often accompanied by drool.

The Olfactory Defense (The Smell): This is the part most people don’t know about. To complete the illusion of a rotting corpse, the opossum’s anal glands release a green, foul-smelling fluid. This musk smells like decay.

Most predators (like coyotes, foxes, and bobcats) are wired to hunt live prey. They may sniff a “dead” animal, but the combination of the lack of movement and the smell of rot triggers an instinct to avoid it, as eating carrion carries a risk of disease. The predator loses interest and walks away.

How Long Does It Last?

Because this is an involuntary comatose state, the opossum has no control over when it wakes up. It cannot just open one eye to check if the coast is clear.

The state can last anywhere from 40 minutes to 4 hours. During this time, the animal is completely vulnerable. You can poke it, prod it, or even pick it up (though we don’t recommend it), and it will not react.

What To Do If You Find One

It is very common for Louisville homeowners to find an opossum in their yard that appears dead, especially after a dog has barked at it.

1. Check for Injuries: Look for visible blood or wounds. If the animal is clearly injured, it needs help. If there are no wounds, it is likely just in shock.
2. Secure Your Pets: Bring dogs and cats inside. The opossum needs time and safety to recover.
3. Leave It Alone: Do not try to move it, bury it, or put it in a trash can.
4. Wait: Check back in an hour or two. In almost every case, the “body” will have simply vanished.

Why Opossums Are Good Neighbors

Before you call us to remove an opossum, consider their benefits. They are nature’s pest control.

• Tick Eaters: They groom themselves constantly and eat thousands of ticks per season, reducing Lyme disease risk.
• Snake Eaters: They are immune to pit viper venom and will eat Copperheads.
• Clean Up Crew: They eat carrion, rotting fruit, and cockroaches.

However, if an opossum has moved into your crawl space or attic, that is a different story. They can cause damage to insulation and ductwork. In that case, professional removal is necessary. But if you just see one passing through or “playing dead” in the yard? Let it be. It will wake up and waddle away soon enough.