Playing Possum: Unraveling the Art of Thanatosis in Opossums
When a possum “plays dead,” it enters a state called thanatosis, essentially feigning death by becoming limp, drooling, and emitting a foul odor to deter predators. This is a last-ditch survival tactic where what possums do when they play dead is tricking a predator into thinking they are already dead, and therefore, not worth eating.
The Dramatic Defense: Introduction to Thanatosis
The opossum, North America’s only marsupial, is known for its resilience and adaptability. However, its primary defense mechanism isn’t speed or strength but a rather theatrical display known as “playing possum,” or thanatosis. Understanding what possums do when they play dead requires delving into the biological and behavioral intricacies of this fascinating phenomenon. This isn’t a conscious decision but rather an involuntary response to extreme stress or perceived danger.
The Biological Basis of Playing Possum
The playing dead behavior is not a voluntary act of strategic acting; rather, it is an involuntary neurophysiological response triggered by extreme stress or perceived threats. The possum’s body essentially goes into shock.
- Hormonal Cascade: Adrenaline and other stress hormones flood the possum’s system.
- Neurological Shutdown: The brain triggers a temporary shutdown of voluntary muscle control.
- Physiological Changes: These include reduced heart rate, slowed breathing, and a drop in body temperature.
The combined effect of these biological changes makes the possum appear lifeless.
The “Playing Dead” Process Step-by-Step
Understanding the precise sequence of events that occur when a possum plays dead provides a clearer picture of what possums do when they play dead. The process unfolds as follows:
- Threat Detection: The possum perceives a significant threat (e.g., predator attack, loud noise).
- Stress Response: The sympathetic nervous system activates the fight-or-flight response, quickly escalating into a state of shock.
- Involuntary Collapse: The possum becomes limp, often falling to its side.
- Appearance of Death: Eyes may glaze over, the tongue may loll out, and drool can accumulate.
- Odor Emission: Anal glands release a foul-smelling, green fluid, further convincing predators of the possum’s demise.
- Predator Assessment: The predator, often deterred by the smell and the apparent lack of a living prey item, may leave.
- Recovery: After the perceived threat passes (which can be several minutes to several hours), the possum slowly recovers and escapes.
Benefits of Playing Dead: A Survival Strategy
The evolutionary advantage of thanatosis is clear: it increases the possum’s chances of survival against predators. Here’s how:
- Deters Predators: Many predators prefer to hunt live prey. A seemingly dead animal is less appealing.
- Confuses Predators: The bizarre behavior can confuse or startle a predator, providing the possum with a window of opportunity to escape.
- Avoids Attack: A predator may think the possum is diseased or poisoned, further discouraging an attack.
The effectiveness of this strategy depends on the predator’s behavior and the possum’s ability to convincingly feign death.
Common Misconceptions About Playing Possum
There are several misconceptions surrounding the “playing possum” behavior. Let’s clarify them:
- Myth: Possums Choose to Play Dead: As stated before, this is not a conscious decision but an involuntary response.
- Myth: Possums Are Always Successful: While effective, it’s not foolproof. Some predators will still attack, even if the possum appears dead.
- Myth: Possums Play Dead for Fun: This is strictly a defense mechanism in response to imminent danger.
Situations When Possums Play Dead
While predators trigger it most often, other situations can elicit the thanatosis response. Understanding these scenarios gives more insight into what possums do when they play dead.
- Predator Encounters: Dogs, cats, foxes, and owls are common predators.
- Loud Noises: Sudden, loud noises can startle the possum into playing dead.
- Human Interaction: Trapping, chasing, or handling a possum can induce the response.
- Traffic: Being near a road can cause the response.
Table: Comparing Opossum Defense Strategies
| Defense Strategy | Description | Effectiveness | Trigger |
|---|---|---|---|
| :—————- | :———————————————————— | :———— | :—————— |
| Playing Dead (Thanatosis) | Feigning death by becoming limp, emitting foul odor. | Moderate | Extreme stress, threat |
| Growling/Hissing | Making defensive noises to intimidate potential threats. | Low | Perceived threat |
| Baring Teeth | Showing teeth in a threatening manner. | Low | Perceived threat |
| Climbing/Escaping | Attempting to escape up trees or other structures. | High | Perceived threat |
Frequently Asked Questions (FAQs) About Playing Possum
Why do possums play dead instead of fighting back?
Possums are not particularly strong or agile fighters. Playing dead is a more effective survival strategy than attempting to confront a predator. Their primary defense is avoidance, and when that fails, thanatosis offers a better chance of survival than direct confrontation.
Is playing dead a learned behavior or an instinct?
It is primarily an instinctual behavior driven by the opossum’s neurophysiological response to extreme stress. While young possums may refine the behavior through experience, the fundamental response is hardwired into their nervous system.
How long can a possum stay in the “playing dead” state?
The duration varies depending on the level of stress and the persistence of the perceived threat. It can range from a few minutes to several hours. Once the perceived danger has passed, the possum will gradually recover.
Does playing dead always work?
No, playing dead is not a guaranteed survival strategy. Some predators may still attack a seemingly dead possum, or they may simply wait for the possum to revive before attacking. Its effectiveness depends on the predator.
Are there any other animals that play dead like possums?
Yes, many other animals exhibit thanatosis as a defense mechanism, including certain insects, reptiles, and birds. Each species has its own specific triggers and physiological responses associated with feigning death.
What should I do if I find a possum playing dead in my yard?
The best course of action is to leave the possum alone. Do not try to move it or interact with it. Simply give it space and time to recover on its own. Keep pets away from the area to avoid causing further stress.
Do baby possums play dead too?
Yes, young possums exhibit the playing dead behavior from a relatively early age. However, their execution of the behavior may be less convincing than that of adult possums.
Is playing dead painful for the possum?
While it is likely a stressful experience, playing dead is not inherently painful for the possum. The physiological changes associated with thanatosis do not cause physical harm.
How can I tell if a possum is truly dead or just playing dead?
Observe the possum for signs of breathing or subtle movement. If there is no obvious injury and the possum is lying limp and unresponsive, it is likely playing dead. However, if there are visible wounds or other signs of distress, it may be injured or deceased.
Do possums have any other defense mechanisms besides playing dead?
Yes, possums can also growl, hiss, and bare their teeth to deter potential threats. They may also secrete a foul-smelling fluid from their anal glands. Climbing to safety is another common defense strategy.
Are opossums nocturnal?
Yes, opossums are primarily nocturnal, meaning they are most active at night. They spend their days sleeping in dens or other sheltered locations. This nocturnal behavior helps them avoid predators and find food.
How can I prevent possums from playing dead in my yard?
The best way to prevent possums from playing dead in your yard is to reduce the likelihood of them feeling threatened. This includes keeping pets indoors at night, securing garbage cans, and removing potential food sources. You can also install motion-activated lights to deter them.