Chen Yuanhui poses with a Mangshan pit viper in the Mangshan Mountain National Nature Reserve, Hunan province. Photo by Zhang Yi/For China Daily

He realized protection required scientific research. So he started a small-scale artificial breeding program in his home. This put the whole family in danger. A bite from a Mangshan pit viper can kill within two hours if the patient does not receive treatment.

Chen has survived more than 20 bites over the past three decades. In 2003, he was bitten as he tried to release a young snake he had treated for an injury. He was unconsciousness for three days and lost a finger.

There is a Chinese saying, "Once bitten by a snake, the mere sight of a rope will scare you for the rest of your life." Chen has defied this by continuing to work with the snakes after his injury.

During the recent decades, he has published more than 40 papers on the species, calculated the wild population and their distribution area.

There are fewer than 500 Mangshan pit vipers in the wild, far fewer than the population of wild giant pandas. Fame can bring trouble for men and snakes alike. As the existence of the rare species became known, smugglers tried to buy the snakes from Chen, but he refused.

"I needed money, but I knew if started selling the snakes, the species could disappear within three to five years," he said.

Chen also refused the help of a foreign zoologist who offered to set up a breeding program outside China. "I told him that China is able to protect the species," he said.

As China's wildlife conservation efforts and public environmental awareness have improved, Chen is no longer alone in protecting the endangered species.

Mangshan Mountain National Nature Reserve was set up in 1993. The species was listed as endangered on the International Union for Conservation of Nature's Red List of Threatened Species in 1996.

In 2004, the Mangshan Museum of Natural History was established, which is dedicated to the conservation of Mangshan pit vipers.

A rare snowfall in 2008, which killed more than 100 pit vipers, forced Chen and his colleagues to speed up research on artificial breeding. So far, over 100 snakes have been born through the breeding program and most have been released into the wild.

Around 200,000 tourists visit the area annually, attracted by the rare pit vipers and the natural scenery of Mangshan Mountain, providing more jobs and higher incomes for local residents.

"I never expected that protecting the snake would also benefit the local people, but it is also important to me," Chen said.

With his silver hair and whiskers, Chen is easily recognized by tourists who often want to take photographs with him. He is always open to meeting those who come to see his snakes.

"Snakes are coldblooded animals. My late wife used to joke that I am also coldblooded. But my heart is warm. I love the Mangshan pit vipers more than myself," Chen said.