Frog Romance Just Got a Little More Interesting


While we can't pretend to know everything about Kermit the Frog's private life, researchers have discovered a new mating habit unique to an Indian frog species. Andrea McCallen/Getty Images
While we can't pretend to know everything about Kermit the Frog's private life, researchers have discovered a new mating habit unique to an Indian frog species. Andrea McCallen/Getty Images

The sex lives of frogs aren't all that mysterious. Or at least they weren't until this month, when a paper published in the journal PeerJ has revealed there's more to anuran sex than we previously thought.

Herpetologists have long believed there to be just six different mating positions possible for the nearly 7,000 species of frogs and toads worldwide. These "amplexus modes" usually involve males climbing aboard his mate and binding her in some sort of "mating hug" while she lays eggs and he fertilizes them, although some species accomplish the same thing by sitting butt-to-butt, or with the male straddling the female's head, or gluing himself with a sticky substance to her back. This isn't to say frog sex can't get weird — oh, it can get weird — it's just that generally we know what kind of predictable weird to expect.

A male Bombay night frog near a clutch of frog eggs, photographed in the middle of a call.
A male Bombay night frog near a clutch of frog eggs, photographed in the middle of a call.
SD Bju/PeerJ

But a research team led by biologist SD Biju from University of Delhi recently added one more position to the Frogga Sutra move roster. The Bombay night frog (Nyctibatrachus humayuni) is small, brown and shy, and native to the Western Ghats, a mountain range that runs along the entire west coast of India. 

Biju first noticed their peculiar mating behavior in 2002, but it took more than a decade to scientifically verify and document it because the frogs are so secretive. Herpetologists are calling this never-before-seen position the "dorsal straddle." 

On nights during the height of monsoon season, male and female Bombay night frogs come out and call to each other. (This in itself is unusual — in all but about 25 known frog species, the females keep pretty quiet during mating season.) 

Once a male and female decide they like the looks of each other, the male clambers onto the back of his lady love and just lightly rests his frog paws on the leaf or branch they're mating on. No squeezing involved, unlike other positions! 

From there, the female lays her eggs and the male releases sperm onto her back, which trickles down and fertilizes the eggs. Check out the whole process in this video: 

"This is a remarkable frog with an unprecedented reproductive behavior," said Biju in a press release. "This discovery is fundamental for understanding the evolutionary ecology and behavior in anuran amphibians."

If the Bombay night frog is doing it, other frogs might be having unusual sex. Keep your eyes open, everyone!