Poison Frogs Are Some Long-Winded Singers
The little devil frog, Oophaga sylvatica, a toxic frog native to Colombia and Ecuador, is learning to sing straight into the face of fear, singing longer and louder despite the fact that numerous predators are more likely to hear it.
According to a study recently published in the journal Proceedings of the Royal Society B, that's because this little devil is extremely confident in its bright coloring, which warns nearby predators of its intense toxicity.
Confident that all but the most reckless of predators will leave it alone, devil frog males were found to be very willing to risk their lives for the chance that a nearby lady frog will hear its love ballads.
This was determined after researchers measured the call, toxicity, and coloration of 170 species of frog across the globe. They quickly identified a very obvious link between intense aposematism - markings that warn predators of a frog's toxicity - and the boisterousness of its mating call.
Compared to the devil frog, less toxic frogs are practically shower-singers, only quietly calling out for a mate when they are well hidden away from the world. These songs are significantly shorter too, lest a well-camouflaged frog give away its position.
Interestingly, the researchers determined that there is a lot female frogs hear in a song. Size, even for the quieter singers, is sexually selected for, where females prefer frogs with a deeper timbre.
Among poisonous frogs, females also select for those that were most toxic, meaning they hone in on the loudest and most confident singers. The length of a song also helps them find the most healthy and fit males.
"Calling is a very demanding activity and only healthy individuals have the capacity to produce continuous bouts of acoustic signals," study author Juan Santos of the University of British Columbia explained to New Scientist.
He added that the toxicity of these frogs is not actually genetic, as they develop high toxicity and a bright aposematism based on how much poisonous alkaloid they get from their insect diet. Selecting for confident singers then may actually be helping females find the most genetically superior hunters.
Still, at the end of the day, the lesson remains one that even human males are well acquainted with. Confidence, above all else, is key.