These frogs get pretty violent to win over females, and then mate upside-down

India is home to a species of frog that displays peculiar mating behaviour. According to a study published in the Harvard Museum of Comparative Zoology’s journal Breviora, these frogs mate and lay their eggs while upside down. An endangered species named Charles Darwin, they are endemic to the Andamans. Scientists from India and the US collaborated on the paper, which says that these frogs hang upside down on the walls of tree cavities filled with water where thehatchlings drop.

This is the first time that such a thing has been observed in any frog species. According to data, there are 7,708 frog species in the world and almost all of them spawn and mate inside water or other terrestrial habitats. Some also follow the method of external fertilisation, where the female lays eggs during mating, while the male releases sperm to fertilise them.

Biologists from the University of Delhi, the Zoological Survey of India, Harvard University, and the University of Minnesota worked together to understand the rare behaviour exhibited by these frogs.

Add WION as a Preferred Source

Professor SD Biju from the University of Delhi, who led the study, says, “This is a remarkable frog and its reproductive behaviour is unique for a number of reasons. No other frog lays terrestrial eggs in an upside-down position within tree holes.”

Also Read:These female frogs refuse sex, eat up males if they don’t like their singing

Professor Biju, who is currently a fellow at the Harvard Radcliffe Institute and an Associate of Harvard’s Museum of Comparative Zoology, added, "Such specialised traits also yield insights into the evolution of reproductive modes and behaviours among anuran amphibians. This discovery is crucial for understanding the species’ interaction with its environment and its essential habitats.”

Fierce fighting to mate

Another aspect of these frogs that has caught the attention of scientists is their mating calls. Instead of the simple, single-type mating call that most frog species are known to practice, the Charles Darwin frogs perform three types of “complex” calls to attract female attention. It gets pretty ugly and violent as well.

They start off with aggressive calls to fend off competing male frogs. If that fails, they start punching and kicking each other, attacking each other even with their mouth, biting and tearing off flesh, and even the head. Whoever wins and successfully mounts the female frog continues to fight the other frogs who now start butting their heads between the two in a bid to separate them. However, Professor Biju says despite being so violent, these fights rarely lead to death.

Scientists say that this method of mating possibly happened to prevent other male frogs from disrupting the mating process.

The study's findings have also become a cause of concern as the loss of natural habitats is forcing the species to thrive in human trash in forests where human activities are altering the environment. Competition for natural breeding sites is forcing them to mate in plastic and metal containers.