Each spring, right at the beginning of monsoon season, an underground concert series starts up in India’s Western Ghats mountain range.
Near steadily growing streams, from beneath the soil, calls begin to ring out: sets of double and triple chirps reminiscent of the clucks of chickens.
After about two weeks of nightly serenades, the singers appear. Thick-limbed, ruddy-skinned, and about the size of clementines, they are male Western Ghats purple frogs, all sung out and ready to mate.
Clambering out of their dirt burrows, the males search for females, who are about three times the size of the males and the colour of ripe eggplants.
Purple frog mating
When a male frog finds a female frog, he shimmies up on top of her and shoves his spade-like forelegs into the skin on either side of her backbone.
The female then piggybacks him closer to a stream. After she has found a suitably calm place, the male uses his feet to squish thousands of eggs out of her body, fertilising them before they fall.
Then they both burrow themselves back underground to wait for next year.
Threats to the purple frog
It’s thought that Western Ghats purple frogs have undertaken this one-day emergence annually for 120 million years, as continents formed and lineages rose and fell.
The timing of the journey is critical, as the eggs take a week to hatch – if the rains come earlier, the eggs may get washed away; late, and they may dry up. Because of this, the frogs are “directly affected by the changing climate,” says Sandeep Das, an expert on the species.
“Early and delayed rains are causing severe loss in their clutch in recent years.” The frogs also fall victim to habitat loss, pollution, and even, during their very brief open-air sojourns, passing cars.
A frog named after a king
To raise awareness of these singular creatures, Das and other experts have given the species a nickname: the Mahabali frog, after the legendary king Mahabali, who also emerges from the underworld for just one day a year.
How to see Western Ghats purple frogs
These frogs leave their underground burrows for only a few hours every year. If you really want to see one, follow their calls starting two weeks ahead of that time, and be ready when they emerge.
Excerpted from Atlas Obscura: Wild Life by Cara Giaimo and Joshua Foer (Workman Publishing). Copyright 2024. Photograph by Navè Orgad (p.183)
Main image: Western Ghats purple frog (Nasikabatrachus sahyadrensis), also known as the Mahabali frog/Navè Orgad
More amazing wildlife stories from around the world
- It's venomous, has an electric organ, glows in the dark and sweats milk – meet the world's most confusing animal
- Bison snot holds the American prairie together. Here's how, according to an ecosystem expert
- Scientists just spent 16 months exploring Earth's oceans – what they found is breathtaking
- A rare and ghostly shape just appeared in the Great Barrier Reef