When it comes to avoiding an unwanted mating, female frogs are capable of doing anything, even to the point of faking their own death. This is the finding of a new study published in the journal Royal Society Open Science, which highlights that these animals are capable of defending themselves against male coercion.
"Previously it was thought that women could not choose or defend themselves from this male coercion," explains the first author of the study from the Berlin Natural History Museum, Dr. Carolin Dittrich, in The Guardian.
However, the research results indicate the opposite. If forced, female European common frogs (Rana temporaria Linnaeus) can deploy a series of defense mechanisms: body rotation, calls for release and tonic immobility (feigning death).
"Our observations show that female explosive-breeding frogs may not be as passive and helpless as previously thought," the researchers write.
To reach these conclusions, the team placed a male frog in a box with two females (one large and one small) and recorded its behavior on video.
Of the 54 females that experienced a male's claws, 83% of them attempted to rotate their body; 48% issued release calls (grunts and squeaks) and rotated their body; and 33% reacted with tonic immobility (stiffness with arms and legs extended in a pose reminiscent of playing dead), along with rotation and calling.
According to their results, these defensive behaviors were significantly associated with smaller female body size. They were the most successful when it came to escaping the males who wanted to procreate without their approval.
"The appearance of the three behaviors together was significantly associated with a smaller female body size, while the rotation in combination with the call was associated with a larger female body size," detail those responsible for this work.
Researchers link tonic immobility as a response to stress. It was more common in young girls, which could be a result of greater stress that comes with less breeding experience.
Despite their results, those responsible recognize some limitations of the study, such as the need for a larger sample to investigate whether smaller females are more successful in escaping.
