Playing dead and spewing blood gets the job done for feinting dice snakes, who have evolved a dramatic but effective way of putting would-be predators off their meal. They’ll stop at nothing, with autohaemorrhaging, convulsive twisting, and even smearing themselves with shit all on the cards.
The impressive performance comes from Natrix tessellata, a semiaquatic species that mostly eat fish and can be found hunting for them across western Europe, northern Africa, the Middle East, and Central Asia to Western China. When it’s not hunting, it’s prey for a wide variety of predators including other reptiles, birds, and mammals.
With so many on your tail, it pays to employ more than one kind of antipredator defense, and several species exhibit a complex array of “don’t eat me” strategies. Death feigning is what the authors of a new study describe as an “especially interesting” antipredator defense, not least because it’s a risky strategy to resist fleeing – and it’s one that the dice snake excels in.
When it looks like the chips are down, their swansong involves a combination of lying motionless in an “I am deceased” posture, smearing themselves with feces and musk, and autohaemorrhaging – a weird trick where animals willingly bleed. The researchers wanted to test if the combination of all these dramatic displays makes for a more convincing (and therefore more effective) go at death feigning, and so they tested 263 dice snakes in the field.
Dice snakes really go the extra mile when it comes to playing dead.
They grabbed dice snakes by the mid-body and immediately saw the animals starting to coat themselves in fecal matter and musk, a smearing behavior that’s thought to put off the predator by making its prey repulsive. They then handled the snakes in a way that mimicked what a predator might do, before placing them down – unharmed – on the floor.
The death feigning kicked in once the snakes were on the ground, as the animals’ mouths lolled open, tongues flaccid. They then timed the death feigning duration, and noted if anything else happened, such as blood dripping from the snakes’ mouths, before identifying their age and sex and letting them go.
The results showed that older snakes were more likely to combine the smearing of feces and musk with feigning dead, and that they tended to spend less time playing dead compared to younger snakes. The researchers suggest this indicates that these behaviors have synergistic effects, making the more complex performances more believable so that the predator is tricked and abandons its disgusting dead meal.
There are some limitations to the findings in that the snakes’ behaviors weren’t made in response to real prey-predator interactions, but it’s a curious insight into the complex ways in which animals have evolved to get out of a bind.
Sophisticated, even if it does leave you covered in your own poop.
The study is published in the journal Biology Letters.
Source Link: Incredible Snake Actors Smear Themselves In Blood And Poop To Play Dead