Snakes regurgitate blood to feign death

The dice snake on Golem Grad, an island in the middle of a lake in North Macedonia, has a unique defense mechanism. When captured by predators, these snakes foul themselves with a mixture of feces and pungent compounds, then play dead by lying motionless with their mouths wide open and tongues sticking out. Some even go as far as vomiting blood to complete the act of pretending to be dead. This behavior has been observed to confuse predators, giving the snakes a chance to escape.

Research published in the journal Biology Letters delves into the effectiveness of feigning death as a defense strategy in the animal kingdom. Many species, including insects, fish, reptiles, and even mammals, play dead when threatened by predators. The act of pretending to be dead can confuse or frighten predators, causing them to relax their claws and provide an opportunity for the prey to escape.

The research led by Vukasin Bjelica, a PhD student at the University of Belgrade, focused on dice snakes on Golem Grad Island. These non-venomous snakes use the tactic of playing dead to deal with their main predators, birds. When captured and provoked, the snakes exhibited behaviors such as smearing feces and pungent compounds on their bodies, spitting blood, and playing dead to fend off predators.

The study found that adult snakes were more dedicated to pretending to be dead, while immature snakes often did so in a shorter time. Playing dead was most effective when there were distractions or other prey around, causing the predator to overlook the snake. While the research provided valuable insights into the behavior of dice snakes on Golem Grad Island, further studies on snake populations in other locations are needed to broaden understanding on this defense strategy in snakes.