Weird Purple Frog Seduces Females From Underground

Meet the Indian purple frog, also known as the pig-nosed frog. Only formally discovered in 2003, the colorful amphibian is an endangered species native to the mountains of India’s Western Ghats.

A photo of an indian purple frog.
An Indian purple frog. Photograph by SD Biju, University of Delhi.

With a chubby, purple body and pointed, piglike snout, it’s unlike any other frog on Earth. Some of the purple frog’s unusual looks are adaptations for its burrowing lifestyle: The animal spends most of the year underground, using its short, stout limbs like spades to dig as far as 12 feet (3.7 meters) below ground. (See pictures of more frogs found in western India, including the meowing night frog.)

When the frogs emerge for a brief period during the monsoon season to mate, the males call out to attract females—not exactly unusual among frogs.

But male purple frogs march to their own tune, scientists have discovered: They call from underground, beneath a thin layer of dirt near the entrance of narrow tunnels filled with loose soil, according to the first detailed description of the purple frog’s advertisement call.

Wily Frogs

For their research, scientists from India’s University of Delhi and the University of Minnesota recorded the males’ calls after heavy downpours, when they’re most vocal.

freshwater species of the weekWhen males call, they contract their muscles and inflate and deflate their vocal sacs, making sounds in short, rapidly repeating pulses—the only type of call detected by the team. These movements disturb the thin layer of soil above them, allowing the researchers to pinpoint their locations, according to the study, published February 7 in the journal PLOS ONE.

Next came the hard part: After recording a male’s song, the researchers quickly dug into the soil to capture the animal. (See “World’s Loudest Animals—Bug With ‘Singing’ Penis, More.”)

Listen to two male frogs communicating.

They had to dig fast, because the wily frogs responded by retreating deeper into the soil. The researchers then measured each male before releasing it back into the loose soil into which it had burrowed.

He’s no Prince, but this Purple One makes his own kind of beautiful music.

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Mary Bates is a freelance science writer living in Boston. She has a PhD in psychology from Brown University where she studied bat echolocation. You can visit her website at www.marybateswriter.com and follow her on Twitter at @mebwriter.

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