A black wolf has been photographed for the first time in the Three-River Source National Park in Qinghai province, confirming the species' existence in China, the World Wide Fund for Nature said on Wednesday.

The environmental NGO said an image taken during a waterbird survey in early October was confirmed by experts this month to include a rare black wolf. 

The wolf had white lips and black fur, completely different from the dark-yellow and gray fur of the common gray wolf, the WWF said. The black fur in wolves is a recessive gene, common among species in North America but rare in Asia.

John Mackinnon, a retired biodiversity conservation scientist, confirmed that it was a black wolf after looking at the image.

"The gene is recessive, which means the black wolf gets the gene only if its parents have it," Mackinnon said. "The gene is very rare, so the chance (that) both carry the gene is very small."

Xie Yan, a researcher at the Chinese Academy of Sciences' Institute of Zoology, said the image is of great significance to the study wolf species in China.

She said experts in North America and Europe have been concerned about black wolves since the 1920s, but there are few reports documenting them in China. "It shows our ecology has improved," she said.

Wei Baoyu, a senior manager for the WWF Wetland Project, said the NGO hopes to carry out research on black wolves in the Three-River Source National Park Administration.