Photos: Out in the field with the frog prince of India

Over 30 years, Sathyabhama Das Biju has led expeditions that have resulted in the discovery of over 100 amphibians across India and Sri Lanka, and as far off as China, Indonesia and Thailand. “Every trip to the field is a different experience, even in the same location,” says Biju, 58, often called India’s leading “frogman”. In his coffers are India’s smallest frog, a rare canopy-dwelling frog thought to be extinct, 14 types of dancing frog. “All our discoveries have been accidental,” he says rather modestly. See the man and his work in pictures.

Amphibian biologist Sathyabhama Das Biju with a golden-backed frog in the Western Ghats. In addition to discovering 105 species so far, Biju has conducted research that proved groundbreaking. He was instrumental in differentiating between the golden-backed frogs in India and those in Sri Lanka, for instance. After a decade-long survey in the Western Ghats and Sri Lanka, analysing DNA and morphology, Biju concluded that were no golden-backs that were common to both countries. Sri Lanka has one species and the Western Ghats has six, each existing in their own narrow geographies.

SD Biju at his lab at the University of Delhi. He is currently dean of the faculty of science. This is where he and his team study the samples and data that they collect in the field, record morphological and anatomical data and conduct DNA analyses. It can take multiple field trips and years of analysis before a new species is formally named.

Biju’s discovery of this rather odd-looking purple frog (Nasikabatrachus sahyadrensis) in 2003 changed his life. Not only had he discovered a brand new family of amphibians and provided evidence of an ancient geographical link between India and the Seychelles, an island now almost 4,000 km away in the Indian Ocean, the frog was also proof of a claim he had made a couple of years earlier — that India had hundreds of amphibian species waiting to be discovered.

The Frankixalus jerdonii, rediscovered in the foothills of the Himalayas by Biju and his team. The tree canopy-dwelling species was thought to be extinct for nearly 150 years, and was rediscovered in a 2007 expedition, after Biju and his researchers realised that the unique mating calls — “a full musical orchestra” — were coming from the tree canopy and not from the ground. The Frankixalus jerdonii was classified as a new genus, characterised by a rare behaviour where the young are fed on unfertilised eggs.

The Nyctibatrachus pulivijayanii (Vijayan’s night frog), a miniature frog less than 14mm long. The Nyctibatrachus, a genus of tiny night frog, is found only in the Western Ghats. The pulivijayanii is named after Vijayan Kani, one of the many tribals who have guided Biju through unfamiliar forests through the years, helping greatly in his research. Kani is from the Agasthyamala hills of Kerala and acquired the name Pulivijayan after surviving a leopard attack (puli is Malayalam for leopard). Biju thought this name apt, he says, given the leopard-like spots on the back of this frog.

Biju led the discovery of a new family of legless amphibians (known as caecilians), which he called Chikilidae, after the Garo word for these creatures. Five species were discovered after 250 soil digs across north-east India, over five years. These amphibians spend their entire lives underground. They look like worms, but are distinguished by their backbone.

Biju has 14 species of dancing frog in his tally. Dancing frogs belong to the Micrixalus family, found in the Western Ghats, and are named after their habit of lifting and waving their hind feet to attract females during breeding season. Seen here is the Mallan’s dancing frog (Micrixalus mallani), which Biju named after another field guide, Mallan Kani, who has been assisting him for 15 years.

Franky’s narrow-mouthed frog (Mysticellus franki) is literally mysterious. It took two years from the discovery of the tadpoles for Biju and his team to finally identify the adults, and another four years before they could announce their discovery to the world. When it was described in 2019, it was awarded its own newly created genus, Mysticellus, derived from the Latin mysticus or mysterious. They disappeared as mysteriously as they appeared to the scientists, who haven’t been able to trace where they live in non-breeding season. Their call sounds like a chorus of insects.