The primitive Mannan tribes people who once plundered the jungles of tropical southern India, destroying the ecosystem and driving the dwindling number of tigers deeper into what was left of their habitat, now risk their lives to protect them.

By guaranteeing the Mannan a comfortable, legal income from Project Tiger, the government has made conservation worth more than poaching, says reserve deputy chief Pramod Kishnan.

“The moment the tiger is gone, that money is gone,” he says. “We are converting the destroyers of the park into its protectors. With their help, we have caught about 150 poachers.”

About 500 Mannan families live in round, thatched huts in a new government settlement on the edge of the park. The men — armed with ancient bolt-action .303 rifles — work mainly as rangers and guides.

The village women make voluntary patrols, giving up one day every two weeks to slog through the jungle.

The only equipment the government gives them is a next-to-useless thin plastic raincoat and a green baseball cap with a tiger face on the front.

“We realise now that we were doing such bad things. It was becoming a desert,” says Leila Kasim as she prepares for a patrol.

In March, wildlife experts and the media suddenly started talking of an alarming drop in big cat numbers across the country, home to almost half the world’s surviving tigers, saying some of the 32-year-old Project Tiger’s showcase reserves now had none.

Prime Minister Manmohan Singh ordered an investigation and announced a special wildlife anti-crime task force.

A century ago, there were about 40,000 tigers in India. They were a major danger to villagers and explorers and a test of hunting skills for flamboyant maharajas and officers of the Raj. Now, officials estimate there are about 3,700, but wildlife experts say the number is closer to 2,000.

The main human pressure in Periyar is the five million pilgrims visiting the Sabarimala temple within the park. But they pay nothing towards the reserve’s upkeep. The temple in honour of Lord Ayyappa is a major site of attraction in Kerala.

Periyar’s rugged terrain has always given tigers more protection from poachers than the relatively flat and open plains of the north.

But their numbers fell anyway as tribal gangs raided the forest, at the heart of the famed Malabar spice coast, for cinnamon, vanilla, cardamom and sandalwood.

Thirty-six-year-old Surindar Sumar and his band of 20, all illiterate, were once one of the most notorious gangs, stripping 10,000 cinnamon trees a year and earning thousands of dollars. Now he is a leading ranger, taking home Rs 3,500 a month.

But the Mannans supplement their park earnings with returns from a government-sponsored pepper growing and marketing scheme.

“We are at peace with the authorities, at peace with ourselves,” Sumar said.