The dawn mist was still clinging to the mangroves when the maneater struck. Mohammed Rasul Hussain, 45, had left his hut in southwestern Bangladesh at sunrise three weeks ago and, with his younger brother, Sheraz, paddled across the river and into the vast Sundarbans forest.

They moored their boat and set off on foot to search for crab, wild honey and firewood in the world's largest mangrove swamp, which straddles Bangladesh's border with India.

Armed with only a machete, Mohammed did not stand a chance when the tiger leapt from the undergrowth, knocked him to the ground and sank its teeth into his neck. Sheraz could only scream in horror — and run.

They buried Mohammed that evening, minus his left leg.

“He knew the dangers of the forest, but he couldn't do anything else to survive,” said Fatima, 30, his widow and the mother of their three children. “It would be better if there were no tigers here.” Like Mohammed, villagers here have always understood the risks of entering the Sundarbans, one of the last refuges of the endangered Bengal tiger.

Spread across 3,700 square miles (9,583sq km) in the Ganges delta, the Sundarbans is home to 440 tigers, according to a joint Indian and Bangladeshi survey done in 2004.

Maneaters have long been a problem here. Almost every village has its “tiger widows” and a shrine to Bon Bibi — the forest goddess who wards off the big cat.

Since a hurricane last November, the conflict between tiger and human has escalated to a new pitch — highlighting the environmental threats to this unique habitat.

Tigers have killed twenty people in the Bangladeshi Sundarbans so far this year, compared with six in 2007 and seven in 2006, according to forestry officials.

Even more worryingly, tigers have started straying into villages on the forest's fringes.

“The situation is quite negative,” says Rajesh Chakma, the head forest ranger in Munshiganj, the worst affected district with 18 fatal attacks this year. “We could see many more attacks before the year's end, as it's mating season now and tigers become more aggressive.”

In the village of Horinagar no one goes out after dark anymore, even to use the lavatory.

On June 20 a tiger swam across the river from the Sundarbans and killed three people before villagers surrounded it, threw a noose around its neck and beat it to death with sticks. They summoned the forestry officials, as is required by law, but those who arrived could not provide help as they had no tranquillisers.

“The tigers never used to come into the villages, never in my lifetime,” says Shri Poti Mundal, 40, whose father and sister-in-law were killed by the tiger. “If they had captured it and released it, it might have come back.”

Other villages in the area have started lighting fires at night or using loudspeakers from the local mosque to scare off any approaching tigers.

Experts on tiger behaviour are unsure exactly what caused the rise in the attacks as they have not had time to do the necessary research. Most of them suspect that one central factor was Hurricane Sidr, which killed 4,000 people and destroyed 20 per cent of the Sundarbans in November 2007. “Tigers have been displaced to this area - and they are territorial,” Mr Chakma said.

Many also blame a “perfect storm” of environmental problems — rising sea levels, the silting up of rivers, annual floods and salination of fresh water supplies.

“The Sundarbans is dying,” said Ainun Nishat, the head of the International Union for Conservation of Nature's Bangladesh office and an expert on the Sundarbans. “The forest is getting degraded, so that means less prey,” he said. “And you must remember that this is not the tigers' natural habitat.”

The Sundarbans — a Unesco World Heritage Site —- is simply the only space left for the tigers in a country slightly bigger than England with a population of 150 million people.

Remarkably, tigers which normally inhabit inland jungle have adapted by learning to swim, catch fish and drink salty water. As fast as the animals have adapted, however, the forest has shrunk further and the human population around it has multiplied to 2.5 million.

Thousands of people now enter the forest every day — many of them former rice farmers whose land was flooded with seawater — pushing ever deeper into the tigers' domain.

It is a struggle for survival that man and beast are both doomed to lose. The United Nations' Intergovernmental Panel on Climate Change predicted last year that rising sea levels could submerge 17 per cent of Bangladesh by 2050, creating 20 million “environmental refugees”.

A 45cm (17.7in) rise in sea levels would destroy 75 per cent of the Sundarbans, according to Unesco, and subsidence means that net water levels are already rising 3.1mm a year in parts of the forest.

Villagers are mostly unaware of such official forecasts but they know their fate is intertwined with that of the tigers.

“The Sundarbans is our national treasure — and our livelihood,” said Athar Rahman Malik, 40, who survived a tiger attack last year and still bears the scars on his head and arms. “If the Sundarbans is alive, then we are alive.”

ENDANGERED KILLER

— The Sundarbans is a Unesco World Heritage Site spread across 3,700 square miles in the Ganges river delta, straddling the border between India and Bangladesh. It is home to an estimated 440 tigers

— Bengal tigers kill by overpowering their victim and either severing the spinal cord or applying a suffocating bite to the throat. The tiger will usually drag its kill to a safe place to eat, away from other predators

— Most tigers avoid all contact with humans - those that become maneaters are often sick or injured and unable to hunt normally, or live in an area where their traditional prey has disappeared

— In 1900 there were an estimated 40,000 tigers in British India, but over the next century their numbers were devastated — first by hunting, and then by poaching and human encroachment on their habitat

— The World Wildlife Fund estimates that there are just 2,000 Bengal tigers left in the wild in India, Bangladesh, Nepal, Bhutan, Burma and China. Of those, an estimated 200-250 are in Bangladesh

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