Thanatosis, commonly known as playing dead, is a natural defense mechanism observed in various animals. For certain snake species, this behavior serves as a survival strategy when faced with perceived threats. By feigning death, these reptiles aim to deceive predators, increasing their chances of escaping harm.
Common Snake Species That Play Dead
Hognose snakes are perhaps the most well-known practitioners of thanatosis, earning them a reputation for their dramatic performances. This group includes the Eastern Hognose Snake, Western Hognose Snake, and Southern Hognose Snake. Their death-feigning behavior is a primary defense when initial intimidation displays, such as hissing and neck-flattening, prove ineffective.
Beyond the Hognose snakes, several other species also exhibit thanatosis to varying degrees. The Garter Snake, widespread across North America, may release a foul musk before going limp and flipping onto its back. Similarly, the Grass Snake in Europe and the Rinkhals Snake in Africa are known to become motionless as a last resort against predators. Other snakes, such as the Banded Coffee Snake of Central America and the Indian Wolf Snake, have also been documented to feign death.
Understanding Thanatosis: The How and Why
When enacting thanatosis, snakes employ physical actions designed to mimic a deceased animal. A snake will typically writhe dramatically before flipping onto its back, exposing its belly. It often lies motionless with its mouth agape and tongue hanging out, creating the appearance of a lifeless state. Some species, like the Eastern Hognose, may also regurgitate food, defecate, or release a foul-smelling musk from their cloaca, further enhancing the illusion of decay.
The evolutionary purpose behind thanatosis is rooted in predator deterrence. Many predators are instinctively drawn to live, moving prey and often avoid carrion, especially if it appears diseased or unpalatable. The strong, unpleasant odors emitted during the act can signal to a predator that the potential meal is unhealthy or has been dead for an extended period. This aversion to non-fresh or potentially diseased carcasses can cause a predator to lose interest and move on, allowing the snake to eventually “resurrect” and escape once the threat has passed. In some instances, such as with Dice snakes, the performance can even include bleeding from the mouth, which may shorten the duration of the death-feigning act by enhancing the perceived unsuitability of the prey.