In the forests of Western Ghats in India, scientists have discovered a surprising new mating position in a group of frogs, one that has never been reported before.
While mating, most male frogs mount and hug their female partners. A male frog can sometimes grasp the female by her waist, for example, or grab her in her armpits.
So far, scientists have recorded six forms of these embraces in all of the world’s more than 6,500 frog species.
But the secretive Bombay night frog (Nyctibatrachus humayuni), found only in the Western Ghats, has revealed a seventh, never-before-recorded form of mating style.
Instead of grabbing the female tightly like males of other frog species do, a male Bombay night frog mounts and loosely rests on the female, holding on to a leaf or branch instead. The team whose research is published in the journal PeerJ has termed this new position the dorsal straddle.
A. Six previously known mating positions known among frog species worldwide. B. New mating position discovered in Bombay night frog. Illustrations from Peerj.
The tiny 5-centimeter long male Bombay night frog then releases sperm over the female’s back and quickly moves away before the female has released her eggs. Unlike other species, there is no contact between the male and the female Bombay night frog while the eggs are being laid.
The researchers think that the sperm most likely trickles down the female’s back and then fertilizes the eggs.
The team has also made another surprising discovery. Among frogs, it is the males that usually call out to attract the attention of females. But the female Bombay night frog has a distinct call, which the researchers think might help them locate mates.
Watch the frogs in action: