These snakes employ thanatosis, or playing dead, when faced with predators.
Golem Grad Island in North Macedonia is home to a type of snake known as the dice snake, characterised by its patterned scales. These snakes have a unique defence mechanism when faced with predators. When grabbed, they put on an elaborate show: they writhe around, emit a strong odour of musk and faeces, and sometimes even appear to bleed from their mouths, all while going completely limp with their tongues hanging out.
Recent research published in Biology Letters suggests that this dramatic display may help the snakes survive. Just as actors use props like fake blood to make scenes more believable, these snakes seem to use their foul-smelling fluids to enhance their performance of death.
This behaviour, known as thanatosis, or playing dead, is observed in various animals, from insects to mammals. Opossums are particularly famous for their convincing portrayal of being dead.
To confirm this hypothesis, researchers tested 263 dice snakes (Natrix tessellata) directly in the field. They noted the occurrence of smearing faeces and musk.
“Our results highlight the functional integration of antipredator behaviours across different phases of predator-prey interactions, emphasising the need for future research to prioritise studying the sequential display of behaviours,” researchers said.
For animals employing this strategy, the stakes are high. While playing dead can confuse or repulse predators, giving the animal a chance to escape, it’s also risky. The success of the tactic hinges on the animal’s ability to remain perfectly still while in close proximity to a predator, which can be quite challenging. The study suggests that the more realistic the performance, the less time the snake has to spend vulnerable while playing dead.