THE worst of the hazards travellers encounter in the mountainous rainforests of southern India is not the elephants, though they occasionally kill people; nor the creepy-crawlies, though the sudden appearance of a foot-long red-legged millipede can startle; nor the spiny-stemmed palms, though they shred unwary walkers' clothes. It is the leeches. If you pause on a walk through the forest, within a minute up to 20 of these brown slimy tubes, ranging in size from minuscule threads to fat worms four centimetres long and a quarter in diameter, leap onto your boots. Attracted by heat, they loop swiftly upwards like caterpillars on speed, scaling a Wellington in as little as 15 seconds. Leech socks—thick canvas affairs tied tightly at the knee—stop those that climb into boots from attacking your feet. But others continue upwards, and, however assiduously you pluck them off, some inevitably make it onto bare skin and sink their teeth into your flesh. As they do so, their salivary glands secrete hirudin, an anticoagulant so effective that the pharmaceutical industry synthesises it as a blood-thinning agent. Even if you locate them and pluck them off—tricky, given their strong grip and slippery surface—your blood flows from their bites for hours. Not surprisingly, Kerala's rainforests are thinly populated. Only the very determined, with a clear purpose and considerable resilience, venture into them. Among those are Sathyabhama Biju Das, an amphibian researcher at Delhi University, his students and his growing band of followers. Mr Biju is the closest thing Indian herpetology has to a celebrity. A Keralan who spent most of his childhood herding cows, he scraped an education, became a plant scientist, but was increasingly drawn to amphibians. “Plants are very boring,” he explains.

In 2003 he discovered nasikabatrachus sahyadrensis, a purple jelly-like creature with a pointed nose and a running gait that makes a sound like a small chicken. It is actually a frog, but so different from other frogs that it has its own taxonomic family; and because its closest relatives are in the Seychelles, the discovery had implications for theories of palaeogeography and species migration in prehistory. It created quite a stir, and made Mr Biju's name. The purple frog “gave me everything in my life,” he says.

That life is devoted to the taxonomy of Indian frogs. Mr Biju wants to preserve as many as possible from a poignant fate: “nameless extinction”. So far he has clocked up one family, seven genera and 57 species—more species than any scientist in India.

Prince of the forest

Frogs are in danger worldwide. According to the Red List of the International Union for the Conservation of Nature, more amphibians are threatened by extinction than any other animal group. A combination of factors—habitat destruction, climate change, a lethal disease called chytrid fungus—puts them under stress. “What's alarming is the speed with which their populations crash,” says Robin Moore, Conservation International's amphibian-conservation officer. “I've seen pools of frogs belly up.”

Yet as even Mr Moore admits, it is hard to get people to care about frogs: “They look at a picture of a frog, and think: that's cool and weird. But that doesn't translate into empathy for its plight.” Nor do amphibians garner the celebrity attention that tigers do. After Leonardo DiCaprio, a Hollywood star, was reported to have donated $1m to tiger conservation, Mr Biju phoned his office to ask for a statement in support of frogs, but the call was not returned.

None of this deters Mr Biju; indeed, he seems to derive moral strength from the sense of being on the side of the underfrog. “I speak for the quiet majority,” he says.

Mr Biju's most fertile hunting-ground is the Western Ghats, a mountain range that runs parallel to India's western coast from Gujarat to Kerala. The southern end, covered in primary rainforest, is frog heaven. There are 181 known species of amphibian in the Western Ghats, 159 of them endemic (that is, found nowhere else). In September, Mr Biju took off for the mountains accompanied by four researchers, one volunteer and your correspondent, in the hope of adding to his formidable roster of new species. The road from Trivandrum to the forest was winding but smooth, the rain fine and sporadic. It was dark by the time the jeep reached its first night stop—a tribal village on the edge of the forest. The team dumped its bags and headed for the river: night-time is the best time for frog-hunting, for they are noisiest then. The hunters moved through the trees towards the calls, with torches strapped to their foreheads. They peered into bushes and trees, and picked at leaf-litter on the forest floor. Catching frogs requires not just sharp eyes (many are tiny, and most well camouflaged) but swift fingers (all are slippery and fast). Familiar species were discarded. Anything curious, novel or sought-after was dropped into a plastic bag to be identified, photographed and then—for these frog-lovers are scientists, not sentimentalists—pickled in formaldehyde. Commerce with a conscience

When day broke, the skies had cleared. The village smelt of rain and warm earth. The team busied itself photographing its catch. The chief photographer was the volunteer, Dr Caesar Sengupta, managing director of a diagnostics company in Mumbai. He used to photograph birds; but, inspired by Mr Biju's campaign, he switched to frogs. His fellow wildlife enthusiasts were initially sceptical about his move, but his frog pictures are popular and he now has 3,000 friends on Facebook. He organised a meeting in Mumbai earlier this year, at which Mr Biju addressed a packed room on the joy of frogs. “Everybody”, Dr Sengupta says with confidence, “is talking about amphibians.”

The fate of India's amphibians hangs largely on the future of its forests. Exactly what is happening to them is not clear. According to the numbers India provides to the United Nations' Food and Agricultural Organisation, the country has had a constant 15,701,000 hectares of primary forest every year since 1990. But localised studies, and the permissions for forest clearances granted by the government, cast doubt on those figures. As economic growth has accelerated so, it appears, has the destruction of forests. The Centre for Science and the Environment, a lobby group, reckons that the pace at which clearance permissions have been granted has doubled in the past five years. In 2009 alone, 87,884 hectares (out of a total of 68m hectares of primary and other forest) were approved for clearance.

Yet while growth damages the environment, it also nurtures a countervailing force: rising green consciousness. That tends to happen wherever economic dynamism threatens a country's natural wealth, but maybe especially so in India. Environmental awareness lies deep in India's political culture. Mahatma Gandhi was an early green, and the original tree-huggers were Indians: the chipko movement used Gandhian methods to prevent deforestation in the Himalayas in the 1980s. At the same time, India's growth in the past 20 years has—while leaving many millions in poverty—produced a large, eco-sensitive middle class.

As the pressure on the environment has intensified, so have public concerns about the side-effects of growth. Since 2006, when Gallup started polling them on the subject, the proportion of Indians who say they are satisfied with their government's efforts to preserve the environment has dropped from 53% to 45%. Gallup's surveys suggest Indians are more worried about their environment than are people in rich countries. In a way, that is surprising. Poorer people tend to focus more on their immediate needs than on the wider world. Yet in most of America and western Europe, the forest cover was chopped down centuries ago, and the rate of environmental destruction has now levelled off. India has more to lose, and is losing it fast. The big question is how concern for the environment and a desire for growth will be reconciled. Politicians are pulled both ways. Jairam Ramesh, until recently India's environment minister, was seen as pro-green; but while he angered the business lobby by blocking some high-profile schemes, he also approved record numbers of clearances. Big companies tend to argue for growth rather than regulation, but environmentalists have some supporters in business—particularly in the IT industry, says Ranjit Daniels, author of a seminal book on the Western Ghats, who runs Care Earth, an environmental NGO: “IT companies want to have cities that are clean and green and look like Singapore.” They are, of course, in the enviable position of requiring little land and water to grow. And they need to appeal, as both employers and suppliers, to well-educated middle-class Indians who—like Dr Sengupta, spending his free time photographing frogs in the rain—are increasingly green. Of elephants and leeches The next day, Dr Sengupta had to return to his diagnostics business, and Mr Biju swept off with him, telling the team to be ready to leave for the deep forest on his return. Instead of taking the opportunity to rest, the researchers disappeared down to the river, to look for more frogs. Drizzle turned into downpour; the path through the village became a stream.

There was no sign of the researchers on Mr Biju's return. When they got back from the river, drenched and frogless, he exploded. Had he not told them how long it would take to get to the mountains? Did they not know how important punctuality was? They would never be decent scientists if they could not follow instructions. They stood, dripping and downcast, while his anger burned itself out.

The journey into the mountains was indeed a long one, broken by an overnight stop at a Kerala Forest Department lodge on the lower slopes because the presence of elephants made driving in the dark too dangerous. The high-wire electrical fence around the lodge seemed ineffective protection, since the building had no electricity supply. The next day Raj Kumar, a forest-department official, joined the team, to keep an eye on the scientists as they headed deep into the woods.

The canopy was 50 feet high; the path, obstructed by boulders and fallen trees, was at times more a river than a road, at others littered with great piles of fresh elephant dung. The two jeeps' drivers, members of forest-dwelling tribes, were astonishingly skilled; but often the wheels spun uselessly in mud and the passengers had to get out and push, to the hooting of lion-tailed macaques in the canopy.

For most of the drive your correspondent was jammed between the senior researcher, Rachunliu Kamei, and the gearstick. Leeches dropped into the jeep from the overhanging vegetation, so she and Ms Kamei spent much of the trip plucking them off each other. Such intimacy makes conversation easy.

Ms Kamei is a 32-year-old tribal from Nagaland, a mountainous state in the far north-east of India. Her father was the first graduate from her small village; she plans to be its first PhD. Among her five sisters are a lawyer, a schoolteacher, a civil servant and Nagaland's first missionary to Africa.

It was while she was teaching biology at St Stephen's College, part of Delhi University, that she developed a longing to be a researcher—probably, she thinks, because of the speed with which the forests are disappearing in Nagaland: “I wanted to catalogue diversity while it's still there.” But until she met Mr Biju, she did not know what subject or professor to go for. It was his passion for his topic that convinced her, and also his determination. “You need a lot of resources in this business, and I knew he would be able to get them.”

To the non-herpetologist, caecilians, the subterranean worm-like amphibians that are the subject of her PhD, are even less appealing than frogs. “I've completed four years of digging for them,” she says. She has a natural authority—the rest of the team call her “ma'am”—and serious pluck. She and Robin Suyesh, one of the other researchers, had just returned from a field trip in Manipur, in the north-east, where they had encountered, among other hazards, gun-toting guerrillas.

In search of the underfrog

After a five-hour climb, the jeeps stopped at Pandimotta, the highest peak in the virgin rainforest on Kerala's border with Tamil Nadu, and the team's destination. The view would no doubt have been spectacular, but it was obscured by foggy drizzle. The accommodation was a small concrete shed, plus an outhouse with half a roof of corrugated plastic, surrounded by a ten-foot deep elephant pit that was bridged by a slippery log. There was no running water, electricity, bathroom or kitchen. The sleeping quarters, for six, was a room two-and-a-half metres by four, with no beds and a damp concrete floor.

The team dumped its rucksacks and went straight off into the dense bamboo bushes to look for frogs. Ms Kamei and Mr Suyesh were armed with kukris—small machetes—for slicing the bamboo stems inside which some frogs breed. The rest picked through the forest litter of fallen leaves and branches. Rain dripped through the canopy. The team stuck at it for a couple of hours, then, with nothing in the bag, headed back for a supper of rice, dal and blisteringly hot chutney. Spirits were low. The researchers huddled around a fire built in the outhouse by one of the locals who had been hired to cook and pull water, then after supper went off once more, returning near midnight.

Over the next three days, the weather varied from fog through drizzle to driving rain and back again.

At times more a river than a road, at others littered with great piles of elephant dung

The team rose at 5am, hunted until midnight and returned only for food. Conversation was sparse, and devoted to frogs; leisure moments to removing leeches, which were dropped into a pile of salt on the outhouse floor. The exception was Mr Kumar, a product of Kerala's fine public education system, who was keen to discuss Shakespeare and Wordsworth.

In the evening, the frog chorus swelled. To the untrained ear it was a bubbling river of sound; to Mr Suyesh, an expert on bush frog calls who can distinguish those of the 40 different species of bush frog in the Western Ghats, the voices of myriad individuals.

It is only recently that environmentalism has established a strong enough footing in India's higher education system to produce a scientist as specialised as Mr Suyesh. Mr Daniels, of Care Earth, says that when he was a student 20 years ago, there was only one university in India that offered a degree in ecology. Now there are four or five in Bangalore alone. Mr Suyesh has also benefited from Indians' widening geographical horizons. He studied at the Animal Communication Lab at the University of Minnesota, where he relished the intellectual stimulation but was unprepared for the snow. And he is also enjoying the widening of professional horizons in India. Indian parents, he says, mostly believe that their children should become civil servants, doctors or engineers. But those traditional ideas have begun to change.

Although in some ways the students resembled those in developed countries, in their work ethic, their willingness to put up with discomfort, their deference to authority, they remained unmistakably Asian. They addressed, and referred to, their professor as “sir”, accepting harsh criticism without a whimper. They were admonished for, variously, disorganisation, unpunctuality, wearing the wrong boots, buying unsatisfactory bananas and failing to think properly as scientists. They were told they were useless and advised to give up science altogether.

Both professor and students, questioned separately, said they regarded this as quite normal. Mr Biju maintained that, far from being useless, his students were exceptional; their talents merely needed honing. The students, asked about their professor's harshness, were indignant at the implied criticism of him. They were privileged to study under him. He was, they said, unusual not just in his brilliance but also in the effort he put into inspiring others. “Students in India are mostly treated like shit,” said one.

Croak for the camera

With each sortie, the team's spirits rose. The haul was growing. The frogs were put in boxes in the corner of the sleeping quarters to await examination and photography. They croaked plaintively through the night.

To the naked eye, many frogs are unremarkable; yet the camera loves them. It highlights their colours and their weirdness. Magnification helps identify them, too: photography is an essential part of modern taxonomy.

But with frogs, it is a tricky business. They are unwilling to sit still, so photographing them involves not just a cameraman and a lights operator but also a couple of nimble fielders. The subject will often adopt an elegant pose, head erect, its bulbous, shining eyes making contact with the camera for a few seconds; then, just as the focus is adjusted and the lights are switched on, it leaps out of view, leaving the fielders to scrabble around for it in the darkness. It can take an hour to get a decent shot of a frog.

The photography session, on the final day of the field trip, lasted well into the night. Through the camera lens, Mr Biju had his first chance to look properly at the creatures that he and the students had caught in the mountains. Straightening up after 12 hours spent crouched over the camera, he announced with quiet excitement that in his view the team had discovered three new species (all pictured). “Unbelievable,” he muttered. “Unbelievable.”