AYESHA RASCOE, HOST:
Ever felt the impulse to ghost that person who keeps hitting on you and just can't take a hint? - you know, just never talk to them again, just disappear. Frogs have taken that strategy to a new level. A new study shows that some female frogs will play dead to avoid mating.
CAROLIN DITTRICH: Usually, they are laying on the side and stretching arms and legs, like, stiffly from the body. So that's the typical position.
RASCOE: That's Dr. Carolin Dittrich. She's a behavioral ecologist at the University of Veterinary Medicine, Vienna. She observed the behavior for the first time while monitoring mating patterns.
DITTRICH: I had one male and two females in a box, and I let them be there for an hour, undisturbed. And I saw in one video that the female appeared dead, so I got a bit worried that something happened.
RASCOE: Scientists have called playing dead tonic immobility. It's one of the strategies females use to avoid mating, along with rotating their body or letting out a call to tell males they're not interested. That's because mating is brutal in the species she's studying. These frogs are known as explosively breeding frogs. They have a very short mating season. Male frogs in this species get so aggressive that the females can fear for their lives.
DITTRICH: Usually, there's more males than females in the breeding aggregation. That means that males are fighting to get access to the females. And sometimes, a lot of males can cling to one female, which leads to the drowning of the female.
RASCOE: Dittrich notes it's just a reflex for the females.
DITTRICH: It seems it's not a conscious decision of feigning death - like, I don't like this male, so I feign death or something like that - but more like a survival tactic or strategy. So the males - sometimes, they still cling to the females even if they feign death or are immobile. And sometimes, they let go.
RASCOE: Dittrich doesn't know if other species play dead to avoid mating. We've all heard of possums, but that's to avoid a predator.
DITTRICH: But I think that when species have similar selection pressures - like big breeding aggregations, more males than females, this short breeding time - I think these selection pressures could lead to the evolution of this behavior in other species, too.
RASCOE: So male frogs - when you see a female playing dead, maybe make a ribbit - or pivot - to another mate. Transcript provided by NPR, Copyright NPR.
