Playing dead (thanatosis) is a common defense mechanism used to fool predators who are looking for signs of movement. But of all the animals you associate with pretending to be dead, snakes aren’t at the top of the list.
A hognose snake will play possum by rolling onto its back and lolling out its tongue from its wide-open mouth. It will also musk so that it smells dead. Snakes of other genera, like the grass snake and garter snake, can sometimes pretend to be dead. Snakes that play dead do so as a last resort to deter predators when their lives are in danger.
Pretending to be dead is something that you see more frequently in wild snakes rather than captive snakes. Snakes that are kept as pets quickly learn that you aren’t a threat/predator, so they don’t need to play dead.
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Are There Snakes that Pretend to Be Dead?
There are many snakes that play dead, and some are well known for this defensive behavior. However, these species are all in the Heterodon species.
These snakes are common across the continental United States. They are non-venomous, despite an urban myth that they can breathe venom on you. Rather than becoming aggressive, these snakes playing possum.
According to the journal of Behavioral Ecology and Sociobiology, hognoses aren’t the only snakes known to play dead.
‘Tonic immobility’ is relatively prevalent amongst snakes, but the number of families involved remains unclear. The snakes referenced as also playing dead include garter snakes and grass snakes.
How Do Hognose Snakes Play Dead?
When other defensive methods fail (hissing, biting, etc), it will pretend to have died. Its performance is unique and convincing to other animals.
- It will roll onto its back, rather than its belly. The snake will coil and curl up before flipping over.
- It will then writhe around, almost as if it’s in pain, quite violently. Eventually, it will become completely still.
- Then, its mouth will hang open with its tongue lolling out. It will remain as still as possible, even if you pick it up. If you try to flip the snake onto its belly, it will immediately flip back onto its back.
In addition, the snake will musk. This is where it produces a foul-smelling, sticky substance from its cloaca. It may also defecate at the same time. The idea is to make itself as unappetizing to threats as possible.
When Do Snakes Pretend to Be Dead?
Playing dead comes late-on in the predation sequence. It’s a last-ditch attempt to get a predator to leave the snake alone. Playing possum usually occurs after the predator has been in physical contact with the snake.
Knowing this, you’re probably wondering if a snake pretending to be dead actually works. The idea isn’t that playing dead will guarantee the snake’s safety. It may only work half the time. But because they only use it as a last resort, a 50% chance is much better than certain death.
Do Other Snake Species Play Dead?
Hognose snakes are the only species known to play dead. Other species can, but do so rarely. Why this is the case isn’t clear. Thanatosis is an effective means of protection, so snakes of a similar small size would benefit.
The reason why only certain snakes play dead comes down to evolution. Different species adopt different defensive mechanisms based on their living environment. Some kingsnakes developed to look like the deadly coral snake, for example.
Why Do Snakes Play Dead?
Snakes pretend to be dead in order to defend themselves. But you may be mistaking their behavior for something else.
Dead Prey Can Make Animals Sick
It’s almost counterintuitive. Playing dead involves remaining still even after a potential predator has found you. You might think that this will make it much easier for the predator to kill you, but it doesn’t.
Many predators actively avoid eating dead prey. A prey item that’s dead may be infested with parasites or bacteria. If eaten, it could cause sickness. For this reason, animals avoid eating dead, foul-smelling prey.
Last Resort Defense Mechanism
Other defensive methods have all failed. However, there’s a chance that playing dead may deter the predator, convincing it not to eat the snake.
Of course, there’s still a chance the predator could eat the snake anyway. But the point is that playing dead is its last chance at survival.
Most Snakes are Slow Movers
Snakes can’t run away. They can try to get away as quickly as they can, but they can’t ‘outrun’ a bird of prey, mongoose, coyote, etc.
This leaves them with the option of fighting. Most snakes try to fight back by making themselves look big and striking with their fangs exposed. But if this isn’t enough to scare a threat away, a snake isn’t left with many options.
That’s where playing dead may come in useful. This is backed up by a simple observation (not scientific research) that gravid, i.e. pregnant snakes will use death-feigning more frequently than non-gravid snakes. Their slower speed makes them far more vulnerable to predators.
Remember that snakes that play dead only do so as a last line of defense. It’s a method that is used when all other defensive methods have failed. Playing possum is rarely exhibited in snakes that aren’t in the Heterodon species.