Female frogs sometimes play dead to avoid excessively agressive attempts at mating from males, a new study has revealed.
The European common frog, known as an “explosive breeding species” for its very short and aggressive breeding season, often gathers in ponds to mate in large numbers. However, the forceful nature of the male frogs can leave a weaker female with few options – feign death, or be killed.
The study, conducted by Dr. Carolin Dittrich and published in the Royal Society Open Science, found that the females of the species developed habits to combat the “increased efforts by males (harassment, forced copulation, intimidation).”
“During these mating events, several males cling to a female, which are mostly unable to get rid of the unwanted males. This can lead to the female’s death,” says Dittrich, an evolutionary and behavioral ecologist who conducted the research as part of the Natural History Museum Berlin.
According to her research, these female European common frogs avoid mating by using the “tonic immobility,” or “death feigning” tactic, allowing them to escape male attention.
“Tonic immobility as a tactic to avoid mating or male harassment has only been observed in a handful of species and only in one other amphibian,” she wrote, noting that her discovery shows that females in the “explosive breeding frog” species “may not be as passive and helpless as previously thought.”
When engaging in this death feigning tactic, the researchers observed the female frogs stretching their limbs out straight from their bodies in a way that could appear similar to rigor mortis.
The study also found that when able, female frogs will use other avoidance behaviors such as “rotation,” involving the turning and twisting of their bodies until they are freed from the males’ grasp, as well as making a call noise that is similar to the calls males make.
The findings on death feigning in European common frogs are quite notable due to there being “very little literature to support other vertebrate species feigning their own deaths to avoid mating,” ABC News reported.
While playing dead can be observed in several other species, the purpose is typically to avoid being killed by a predator, not a mate.
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