“Boom! Play dead! All right, boy … Have a cookie. ” Apart from training our dogs to feign death for a few seconds for our satisfaction or amusement, we are used to seeing animals in documentaries that, faced with the threat of a predator, instead of fleeing, play dead in hope. not to be eaten.
“Playing dead” in science is known as thanatosis or tonic immobility, and so far it has been described in fish, birds and mammals. One of the best known cases is that of the North American opossum ( Didelphis virginiana ), which, as can be seen in the photo in the article, even sticks its tongue out and begins to smell stinky to avoid being eaten. A behavior that they have in common with guinea pigs, quail, sharks and snakes, such as the blue snake ( Drymarchon melanurus ).
Rosalind Humpreys, a graduate student at the University of St. Andrews in Scotland, explains to Nat Geo that “generally, scientists do not have much information about this intriguing behavior, as it is difficult to document it in the natural environment and there are ethical concerns about it. when designing laboratory experiments in which predators attack their prey ”.
However, at least two other reasons have been discovered why animals can play dead, alternative to not being eaten. These are:
Faking death for food
Pretending that you are dead to put something in your mouth seems to be common in fish. This behavior is used as a hunting strategy, in which species such as the Central American cichlid ( Parachromis friedrichsthalii ) or the abbot fish ( Mycteroperca rubra ) pretend to be dead at the bottom of the lakes and wait for the arrival of other fry, small fish more little ones, who will try to eat their “corpses”. By having them close, these actors wake up from their deadly sleep and gobble them mercilessly.
Faking death for sex
Sexual cannibalism seems to be quite present in different species of arthropods. In the case of spiders of the Pisaura mirabilis species, the males have found a strategy to avoid their tragic end. The latter, when offering the bridal gift to the female, which is usually food, plays dead and remains attached to the package. When the female approaches to enjoy the delicacy, he wakes up, begins to copulate with her and quickly runs away. This fact proposes that simulation of death evolved as an adaptive mating strategy for males to avoid being eaten. According to Trine Bilde, a professor of biology at the University of Aarhus in Denmark, Nat Geo, “playing dead seems to be an attempt at mating by the male in addition to or instead of being an anti-predatory strategy, as it may be useful for both purposes”.
As we can see, dying can have multiple functions, and we are sure that, as always, science will continue to discover even more. We recommend that you watch the TedEd video above to find even more amazing examples of death actors in the animal kingdom.
References:
Peterson, C. (2021, April 30). Many animals pretend to be dead, but not always so that they are not eaten. National Geographic. https://www.nationalgeographic.es/animales/2021/04/muchos-animales-se-hacen-los-muertos-pero-no-siempre-para-avitar-depredadores
Bilde, T., Tuni, C., Elsayed, R., Pekár, S., & Toft, S. (2005). Death feigning in the face of sexual cannibalism. Biology Letters, 2(1), 23–25. https://doi.org/10.1098/rsbl.2005.0392
Tobler, M. (2005). Feigning death in the Central American cichlid Parachromis friedrichsthalii. Journal of Fish Biology, 66(3), 877–881. https://doi.org/10.1111/j.0022-1112.2005.00648.x
