Dice Snakes Fake Their Own Deaths With Gory, Poop-Filled Theatrics

When attacked by a predator, the reptiles can play dead with convincing detail, employing blood and feces for the show

Two side by side photographs of dice snakes faking death, with the snake on the right filling its mouth with blood.
Dice snakes feigned their own deaths with a variety of mechanisms, including filling their mouths with blood (shown right). Bjelica and Golubović, Biology Letters, 2024

All the world’s a stage, and all the dice snakes merely players.

The nonvenomous, water-loving reptiles—named for their dotted underbellies—are some of the animal kingdom’s most dramatic actors, new research finds.

Because they inhabit so many ecosystems, different dice snake populations protect themselves in a variety of ways. Some individuals have been known to bite, make themselves appear large or flatten their heads to resemble a venomous snake. But at least one population of dice snakes takes “playing possum”—also called “thanatosis” or “apparent death”—to the extreme.

Not only will the snakes feign a painful death by twitching and writhing, but they’ll soil themselves with musk and feces, then fall limp with their mouths open and tongues dangling. Some will even punctuate the performance by filling their mouths with bubbling blood.

These theatrics were observed by Vukašin Bjelica and Ana Golubović, both ecologists at the University of Belgrade in Serbia, when watching snakes on the island of Golem Grad in North Macedonia. Published this week in the journal Biology Letters, their analyses add new insight to the study of antipredator behaviors: the variety of mechanisms that prey species have adopted to protect themselves from being eaten.

Faking death comes with a high risk for the snakes, if the predator is undeterred—but it also promises a high potential reward of escape. “They really commit to the role, depending on the individual,” Bjelica tells the New York Times Asher Elbein.

A photograph of a grey-green dice snake, looking straight into the camera
Dice snake populations stretch across Europe and Asia, and their antipredation mechanisms vary. Mircea Nita under CC BY 2.0 DEED

On Golem Grad, which is sometimes called “snake island,” the dice snakes’ main predators are birds. Like the reptiles, the two scientists also did a bit of acting—they captured 263 snakes by lunging at them and grabbing the middle of their bodies, as avian hunters would. They gently handled, stretched and pinched the snakes, then, mimicking a predator having second thoughts, the researchers placed them carefully on their backs moved a distance away.

The team observed that just under half (124 snakes total) smeared feces and musk on their bodies within 30 seconds of being captured, while about 10 percent (28 snakes) bled from the mouth. Just 11 snakes committed to all three defenses—poop, musk and blood.

Researchers also noted differences in how individual snakes faked their deaths. Those that didn’t employ bodily fluids or odor lay limp for up to almost 40 seconds. The ones that deployed all three defenses committed to apparent death, on average, for two seconds less than those that didn’t.

“Two seconds might not be a lot but can be just enough for a snake to mount an escape if the predator backs away from attacking it,” Bjelica tells Science News’ Richard Kemeny. “Even the smallest chance can make a difference in being eaten or not.”

Spending less time on the death-faking theatrics means the snakes can more quickly get out of the potentially dangerous grip of a predator.

While engaging in thanatosis, some snakes were incredibly rigid, while others were so limp the research team could arrange them into heart shapes, the New York Times reports.

Feigning one’s own death for the purpose of defense is hardly uncommon in the animal kingdom. “Some say it is a conscious response, while others are adamant it is not,” Bjelica says to CNN’s Issy Ronald. “One theory is that it is the ‘most primitive’ defense response, similar to freezing in a high stress situation.” Even humans might do it—as is advised when confronted with an attacking brown bear.

Some animals fake their own deaths for predatory purposes. A fish called a cichlid will lie on the ground until other curious fish swim by, then spring to life and eat them. For others, playing dead might be a way to avoid mating.

The researchers’ study of dice snakes has prompted further questions from other scientists, such as whether life experience can explain why some individual snakes don’t engage in all three defense mechanisms.

And scientists still have much to learn about Golem Grad’s birds, as well. “Why are they deterred by ‘dead’ animals, especially since they just saw them alive?” Katja Rönkä, an ecologist at the University of Helsinki in Finland who was not involved in the study, says to Science News.

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