On the path to the summit of Mount Emei in Southwest China's Sichuan Province, visitors can spot monkeys pestering tourists for food.

"Numbered more than 1,200, the monkeys on Mount Emei are known for extorting food out of tourists," said Jia Xiaobing, a monkey keeper on Mount Emei.

"But many of them are in poor health because tourists have given them too much rich food with high sugar and salt content," he told China Daily.

Many of the monkeys have become so fat that there was a popular local saying several years ago that "old women on Emei can climb trees more quickly than monkeys, and the fat monkeys on Mount Emei are like pigs."

"What's worse, many of them suffer from hypertension and diabetes," said Wu Jian, an official with the Marketing Department of the Mount Emei Management Committee.

The monkeys on Mount Emei are Tibetan macaques, a kind of woolly monkey named after a French zoologist. An adult Tibetan macaque usually weighs about 25 kilograms, but on Emei, one weighed 45 kilograms when the Mount Emei Management Committee started helping them slim in 2003.

The committee forbids tourists to feed monkeys in the reserve with their own food. Instead, they can spend 2 yuan (26 cents) buying a small pack of corn or peanuts from keepers in the reserve.

"Thanks to publicity, an increasing number of tourists know the plight of the monkeys and no longer feed them with their own food," Jia said.

The result is encouraging. Feng Qingchuan, deputy chief of the committee, says most of the monkeys in the reserve now weigh around 30 kilograms.

The monkeys on Mount Emei live in groups of 15 to 60.

Led by a monkey king, who has all the female monkeys as his spouses, a group lives in a certain territory and fights off intruders from any other group.

"To protect their sphere of activity, two rival groups will fight and both suffer from serious injuries," said Hao Jian, a producer for Sichuan Television who has been observing the monkeys for about 10 years.

The monkey king changes every four to five years.

"When a king is too old to fulfil the task of reproduction and to lead the group," Hao said, "he is replaced by another strong male monkey."