Despite the male frogs’ impressive singing, female frogs often force them to be quiet and mate before their songs are even through.
A new study, published in the latest issue of the journal Science, determined that the female tÃºngara frog’s perception, or what she hears from her environment, is just as important as what the males are singing to her. A primary reason is that bats are also often listening, waiting, and getting ready to eat… frogs.
Karin Akre of the University of Texas and colleagues found this out after studying the male frog’s singing. She discovered that the female frogs who love them â€” as well as theÂ bats who eat the frogs â€” only listen to the males for so long. They then make their move, even if the males aren’t finished singing yet.
As you can tell from the frog song recording, the mating calls of this species include a whine followed by a series of grunts, or “chucks.”
The researchers played different tÃºngara frog songs to female frogs and frog-eating bats on a stereo in order to see which speaker they approached first. Akre and her team observed that the female frogs and the bats did not always go toward the speaker producing the most “chucks.” Instead, their preference seemed to depend upon theÂ ratio between “chucks.” For example, female tÃºngara frogs always preferred two “chucks” to one. But, they didn’t always prefer three “chucks” to two.
These findings suggest that female frogs are forced to choose their mates, based on their vocal skills, very quickly.
In addition to fear of being a bat dinner, the female frogs could become less choosy as the males’ songs get longer because it becomes harder to tell the difference between two songs as they both increase in length.
Both female tÃºngara frogs and bats therefore limit the length of male mating calls for this species, preventing the songs from becoming too elaborate over time. My guess is that similar pressures must limit vocalizing in other animals. The ultimate “shut up” is to eat the singer. Per the below photo, that happens a fair amount to crooning frogs and their fans.