Whoever discovered the Indian purple frog probably didn’t realize it was a frog right away—this curious animal looks more like a cross between a hippopotamus, a shrew and a regular frog. It’s got a wide, bloated body, tiny round eyes and stout limbs. It’s also called the pig-nosed frog, on account of its most peculiar feature—a protruding snout.
The purple frog, or Nasikabatrachus sahyadrensis, spends nearly its entire life underground in the Western Ghats of India. Though it’s lineage has been around long enough to have witnessed dinosaurs, the species was only discovered in 2003.
The Western Ghats are a mountain range about 1,000 miles long, and lie in the southwest part of the country. They’re even more ancient than the Himalayas, having formed when the prehistoric continent Gondwana broke up.
The lineage of the purple frog makes it a “living fossil”—it’s been thriving and evolving independently of other frog families since the Cretaceous period, at least 66 million years ago. This occurred millions of years before the formation of the Australian and Antarctic continents, the last to separate as Gondwana broke apart.
The Closest Relative Of The Purple Frog Is On An Island 2,500 Miles Away
The montane rainforest home of this strange-looking species is considered a global biodiversity hotspot and an evolutionary transition zone by UNESCO. This means that the Ghats host thousands of species that are a distinctive genetic blend of Asian and African life forms, and found nowhere else on the planet.
However, much of this unique habitat has been continuously cleared for plantations like coffee, cardamom and ginger, since British colonization. In fact, the Western Ghats were a point of fascination for the British, who built holiday homes here and planted exotic timbers.
The family Nasikabatrachidae includes only two species: the purple frog and a close relative, described in 2017, both found in the Western Ghats. Surprisingly, the closest relatives of these frogs live thousands of miles away across the Indian Ocean. Research has shown that the closest lineage to Nasikabatrachidae is the family Sooglossidae, a group of frogs located 2,500 miles away in the Seychelles islands.
This ancient connection is one of many biological clues supporting the former geographic links within the Gondwana supercontinent, which began breaking apart into today’s continents around 180 million years ago.
Its evolutionary significance makes the challenging discovery of this species a huge win for biologists. Though purple frog tadpoles were described as far back as 1917, it was as late as 2003 when an adult was finally described.
However, it had already been known to local communities who had documented several specimens earlier. These were unfortunately overlooked by the scientific community for ages.
The Purple Frog’s Alias Is Inspired By A Banished God
Purple frogs spend their life underground, and are efficient diggers. They use their wedge-shaped skull and strong limbs to dig headfirst through the soil, which must be loose, aerated and sheltered by a thick canopy. They use their elongated snout to feed on termites, ants, earthworms and other invertebrates.
Throughout the whole year, they emerge from underground for just a few days, compelled by the urge to mate.
They generally come out at the onset of the Indian monsoon (rainy season). During this time, the frog’s sucker-like snout and flat, round body help it cling onto wet or submerged rocks as it scouts for the perfect mate. Adults retain the snout and strong jaw they developed as tadpoles, which help in clinging.
The large females usually carry the smaller males on piggy-back, and the pair will traverse precarious rocks and water bodies for the ideal stream to lay eggs into.
The tadpoles of the purple frog are eaten by Indigenous communities in southwest India, as they are thought to possess medicinal properties. Sometimes, children are made to wear amulets made out of the frog, believing that it would help alleviate their fear of storms in this extremely rain-fed region.
Available only just before torrential rains each year, the tadpoles are considered a local delicacy. This practice, along with the deforestation of the frog’s habitat for commercial purposes, are major threats to this already endangered and understudied species.
Local folklore in southwest India about a banished god named Mahabali has inspired the pseudonym “Mahabali frog”. The god was thought to have been tricked into giving up his kingdom, and exiled to the underworld. He was allowed to emerge just for one day to meet his devotees—much like the purple frog.
A Fast Fading Amphibian Wonderland
The discovery of the purple frog was considered a once-in-a-lifetime event, and reignited global interest in conserving the Western Ghats, where around 100 new amphibian species are discovered every decade.
However, it is extremely vulnerable to climate change, being already prone to high rainfall. Unchecked construction of dams and clearing of forests for commercial plantations are increasing risk of land erosion, habitat loss and local extinctions.
There are few breeding sites that the purple frog frequents, and they all happen to occur outside protected areas. While there are no population estimates, local communities have admitted that populations were far higher a few decades ago, and seem to be dwindling fast.
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