Animal welfare activists Wen Zhenyu and Luo Xinmei are trying to halt the illegal sale of endangered animals for food and medicines in the markets of Guangzhou in China guardian.co.uk

Stewed turtle cures cancer, crocodile meat relieves asthma, pangolin scales regulate menstruation and scorpion venom helps stroke victims.

Such is the traditional wisdom in Guangdong province, where animal markets teem with snakes, scorpions, salamander and dozens of different species of birds and turtles, some of which are endangered and all of which are fated to end their lives in restaurants, pharmacies or pet cages.

Eating rare wildlife is normal in southern China, but a growing group of student activists is trying to do something considered far stranger: they are trying to save them.

The nascent NGO conservation movement is stepping in where the authorities have had limited success by monitoring markets and restaurants, reporting sales of endangered species and trying to change the consumer culture. Among the youngest of several small groups is the Asian Turtle Rehabilitation Project, established earlier this year to save the reptiles from the soup pot.

The founding members say they are trying to cross the divide between the culture in which they were raised and the global conservation concerns they have been exposed to via the internet and schooling.

They are surrounded by people who think it's a wasted effort. "They disapprove of this activity. They think turtles are small animals only good for eating, so why bother saving them," says Luo Xinmei, a local student. "Almost no one in Guangzhou realises this is a centre of the illegal wildlife trade."

They are up against tradition and economic growth. Guangdong is the richest and most powerful province in southern China, where the appetite for exotic animals and plants is seen as extreme even in most other regions of China.

The main reason is Chinese traditional medicine, which lists curative qualities in many exotic animals. It is believed that the wilder the animal or plant, the better the effects. A popular saying has it that people here will eat anything with four legs except a chair, anything that flies except a plane and anything in the water except a boat.

Demand dropped briefly after 2003, when the Sars crisis was blamed on pathogens spread by civet cats and other wild animals. But it has surged back since as rising incomes allow more consumers to indulge in foods that were once considered delicacies for the very rich. A survey by the conservation group Traffic last year found that almost half of city dwellers had eaten wild animals in the previous 12 months.

The impact has been devastating. While international attention tends to focus on big mammals such as the Sumatran tiger and the giant panda, many reptiles have quietly been pushed to the brink of extinction, including the three-stripe box turtle, the Rogi Island snake-neck turtle and the Malaysian giant turtle. Turtles are among the most threatened because they breed slowly and their meat is considered good for longevity.

Raising awareness takes a number of forms. The group has secretly taken images of a turtle being butchered and posted them online. But its main job is monitoring. On a recent visit to the city's Qingping and Huadiwan markets, Wen Zhenyu identified big headed turtles, pig-nosed turtles, Chinese three-striped box turtle and elongated tortoises among the many species that are meant to be protected by international treaty.

While China is not the only culprit in the consumption of wild animals, it is the biggest. And its impact is being felt across the region. In February, ­Vietnamese authorities seized a record haul of ­illegally harvested wildlife products, including two tons of tiger bones, bear paws and gall bladders. ­Reports the same month from Laos revealed the ongoing poaching of tiger. The biggest market for these products is China, where a tiger's bones and penis can fetch $70,000.

The authorities launch occasional raids on restaurants and dealers. Last month, Guangzhou wildlife protection officials intercepted a cargo of smuggled golden pheasant, sand badger, leopard cat and other animals.

The Guardian found two food outlets in the Honghua hot spring resort outside Guangzhou openly breaking the law by serving pangolin and other protected animals. The Huasheng restaurant charges 1,000 yuan (about $150) per kilogram of pangolin meat. "You need to pay in advance and then we will find one for you," said an employee. "We can cook it in a hotpot or braise it in soy sauce." Nearby, the Liyuan Meiwei restaurant illegally offers cobra. "It is 100 yuan per half-kilo," said a waiter. "We get it from the wild."

Conservationists believe police alone cannot solve the problem. "We need to build consumer awareness so people move away from unsustainable consumption towards a feeling of stewardship," said James Compton, the Asia Pacific co-ordinator of Traffic.

Late last month, activists from another group, Green Eye, scored a major victory by protesting outside a Guangzhou restaurant in which a nurse shark was held in a tiny tank in which it could barely move. With banners reading "No consuming, no killing" in English and Chinese, the campaigners received widespread coverage from local news channels. They eventually secured the release of the shark into the local marine park.

Zheng Yuanying, of Green Eye, said the focus was not on the stall owners but on the consumers. "We avoid conflict. We just try to make suggestions. But some people think we care about animals too much."

For many species, it may be too late. The Wildlife Conservation Society reports a sharp decline in the diversity of freshwater turtles, snakes and frogs in the wild, though many species, including crocodiles, are being bred successfully in captivity.

At Qingping market, a veteran snake seller says the market sells fewer species than before because many animals are extinct and the authorities are conducting stricter checks. But he admits to selling some protected species under the table. "Even if people know an animal is endangered, they will eat it if they have a disease that cannot be cured with other types of medicine."

One notorious market in Nansha has been closed, but conservationists fear the wild animal business is simply being pushed underground.

At 4am in a dark suburb of Taiping, about an hour's drive from downtown Guangzhou, the Guardian found exotic animals traders covertly plying their wares out of sight of the authorities and conservationists. The three long rows of sheds resembled a cramped and dirty zoo filled with wire cages: long and tall for the herons, flat and low for the civet cats. Ostriches have room to move their necks, but not their bodies. There are similar markets throughout southern China.

The activists say the key is changing attitudes. "We try to educate people that turtles are not only pets and not only food; they are also a friend of ­humans," Wen Zhenyu says.