Photo story: guardian of Francois' leaf monkeys in Mayanghe National Nature Reserve, SW China

Xiao Zhijin observes Francois' leaf monkeys in the Mayanghe National Nature Reserve in Guizhou Province, southwest China, March 17, 2022. Xiao Zhijin has been working in the Mayanghe National Nature Reserve for 33 years, researching and guarding Francois' leaf monkeys. Also known as Francois' langur, the species is one of China's most endangered wild animals and is under top national-level protection. It is also one of the endangered species on the International Union for Conservation of Nature red list. (Xinhua/Yang Wenbin)

File photo taken on May 17, 2018 shows Francois' leaf monkeys in the Mayanghe National Nature Reserve in Guizhou Province, southwest China. Xiao Zhijin has been working in the Mayanghe National Nature Reserve for 33 years, researching and guarding Francois' leaf monkeys. Also known as Francois' langur, the species is one of China's most endangered wild animals and is under top national-level protection. It is also one of the endangered species on the International Union for Conservation of Nature red list. (Xinhua/Yang Wenbin)

Xiao Zhijin records Francois' leaf monkeys with a mobile phone in the Mayanghe National Nature Reserve in Guizhou Province, southwest China, March 17, 2022. Xiao Zhijin has been working in the Mayanghe National Nature Reserve for 33 years, researching and guarding Francois' leaf monkeys. Also known as Francois' langur, the species is one of China's most endangered wild animals and is under top national-level protection. It is also one of the endangered species on the International Union for Conservation of Nature red list. (Xinhua/Yang Wenbin)

Xiao Zhijin observes Francois' leaf monkeys through binoculars in the Mayanghe National Nature Reserve in Guizhou Province, southwest China, March 16, 2022. Xiao Zhijin has been working in the Mayanghe National Nature Reserve for 33 years, researching and guarding Francois' leaf monkeys. Also known as Francois' langur, the species is one of China's most endangered wild animals and is under top national-level protection. It is also one of the endangered species on the International Union for Conservation of Nature red list. (Xinhua/Yang Wenbin)

Xiao Zhijin works in the Mayanghe National Nature Reserve in Guizhou Province, southwest China, March 17, 2022. Xiao Zhijin has been working in the Mayanghe National Nature Reserve for 33 years, researching and guarding Francois' leaf monkeys. Also known as Francois' langur, the species is one of China's most endangered wild animals and is under top national-level protection. It is also one of the endangered species on the International Union for Conservation of Nature red list. (Xinhua/Yang Wenbin)

Xiao Zhijin observes Francois' leaf monkeys through binoculars in the Mayanghe National Nature Reserve in Guizhou Province, southwest China, March 17, 2022. Xiao Zhijin has been working in the Mayanghe National Nature Reserve for 33 years, researching and guarding Francois' leaf monkeys. Also known as Francois' langur, the species is one of China's most endangered wild animals and is under top national-level protection. It is also one of the endangered species on the International Union for Conservation of Nature red list. (Xinhua/Yang Wenbin)

Aerial photo taken on March 17, 2022 shows a view of the Mayanghe National Nature Reserve in Guizhou Province, southwest China. Xiao Zhijin has been working in the Mayanghe National Nature Reserve for 33 years, researching and guarding Francois' leaf monkeys. Also known as Francois' langur, the species is one of China's most endangered wild animals and is under top national-level protection. It is also one of the endangered species on the International Union for Conservation of Nature red list. (Xinhua/Yang Wenbin)

Aerial photo taken on March 17, 2022 shows a view of the Mayanghe National Nature Reserve in Guizhou Province, southwest China. Xiao Zhijin has been working in the Mayanghe National Nature Reserve for 33 years, researching and guarding Francois' leaf monkeys. Also known as Francois' langur, the species is one of China's most endangered wild animals and is under top national-level protection. It is also one of the endangered species on the International Union for Conservation of Nature red list. (Xinhua/Yang Wenbin)