Snakes Fake Dying Using 'Dripping Mouthfuls' of Blood

A species of snake that fakes its own death to avoid being being eaten by predators uses some pretty gory tactics.

Dice snakes put on a convincing show of dying by lying still, with some upping the ante by defecating, leaking blood from their mouths and releasing a foul-smelling musk from their butts.

These dramatic flourishes allow the snakes to spend less time faking their own deaths than their cousins who don't get body fluids involved, according to a new paper in the journal Biology Letters.

Faking one's own death, also known as apparent death, is a tactic used by a variety of species from across the animal kingdom to avoid being eaten by predators. Predators often prefer live prey and may be less likely to eat an animal if they believe it is already dead, especially if they rely on the thrill of the chase or the movement to trigger their hunting instincts. Playing dead can also give a prey animal a chance to escape when the predator is momentarily distracted or decides to leave the "corpse" behind.

According to the paper, dice snakes—non-venomous snakes native to Europe and parts of Asia—are one such animal that fakes its own death. Some only lie still, while others ooze blood from their mouths and roll in their own feces to add to the ruse. Researchers observed 263 dice snakes and saw that 124 went the extra mile by smearing themselves in feces, while 28 leaked blood from their mouths.

"When captured, they will vigorously struggle and hiss while expelling and coating themselves in musk and feces. Eventually, they will become immobile, with a gaping mouth and protruding tongue in a [death feigning] display," the researchers wrote in the paper. "The occurrence of [autohemorrhaging] was noted, which was observed during [death feigning] either as small pools of blood or as dripping mouthfuls."

"Seeing all the different behaviours exhibited immediately prior to and during [death feigning], it is not inconceivable to consider that some of these behaviours work synergistically with one another to make the entire [death feigning] display more dissuading to the predator, thus enabling prey animal to exploit the learned aversion of predators towards sick or dead prey."

They found that the snakes that used the blood and feces approach spent 2 seconds fewer faking their own deaths than the ones who didn't, implying that these tactics are synergistic and enhance each other.

"Our results affirm our hypothesis: dice snakes that smeared themselves in musk and feces prior to [death feigning] and had [autohemorrhaging] during [death feigning] spent significantly less time in [death feigning]," the researchers wrote. "Our results highlight the functional integration of antipredator behaviours across different phases of predator–prey interactions, emphasizing the need for future research to prioritize studying the sequential display of behaviors."

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