Xiao Zhijin's routine has been unchanged for decades. At 8 am he treks several kilometers to a river valley, bringing breakfast to his friends of 26 years. No words are spoken, but the communication is excellent.

Those waiting for breakfast are Francois' langurs, one of the world's rarest monkeys. Named after Auguste Francois (1857-1935), a French diplomat based in southern China, the monkeys have a distinctive look with black, silky hair and distinctive white sideburns that grow from their ears to the cheeks.

Xiao, 52, first came into contact with the monkeys as a forest ranger in 1987, but it was another 10 years before he actually took charge of monitoring and taming them at the Mayanghe Nature Reserve in the Yanhe Tujia autonomous prefecture of Guizhou province.