Xiao Xiao, a female Francois' langur, is pictured with her newborn twins at Chimelong Safari Park in Guangzhou, south China's Guangdong Province, May 13, 2018. Xiao Xiao gave birth to the pair of unlike-sex twins here in April. Francois' langurs babies are born with bright orange fur which turns black within two to three months. The Francois' langur is listed as endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. (Xinhua/Liu Dawei)

Xiao Xiao, a female Francois' langur, is pictured with her newborn twins at Chimelong Safari Park in Guangzhou, south China's Guangdong Province, May 13, 2018. Xiao Xiao gave birth to the pair of unlike-sex twins here in April. Francois' langurs babies are born with bright orange fur which turns black within two to three months. The Francois' langur is listed as endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. (Xinhua/Liu Dawei)

A pair of newborn Francois' langur twins are pictured at the Guangzhou Chimelong Safari Park in Guangzhou, capital of south China's Guangdong Province, May 13, 2018. The pair of unlike-sex Francois' langur twins were given birth to by their mother Xiao Xiao here in April. Francois' langurs babies are born with bright orange fur which turns black within two to three months. The Francois' langur is listed as endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. (Xinhua/Liu Dawei)

Xiao Xiao, a female Francois' langur, is pictured with her newborn twins at Chimelong Safari Park in Guangzhou, south China's Guangdong Province, May 13, 2018. Xiao Xiao gave birth to the pair of unlike-sex twins here in April. Francois' langurs babies are born with bright orange fur which turns black within two to three months. The Francois' langur is listed as endangered on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. (Xinhua/Liu Dawei)