Rare animals: Sichuan golden monkey.

The phylogenetic tree of snub-nosed monkeys has always been controversial about the classification within the genus of the snub-nosed monkey. It has been observed that mutual breeding is fertile in captivity, and it is believed that there should be four subspecies of a species. At present, there is a consensus that the back-nosed monkey was originally a species distributed in the Hengduan Mountains, and later evolved into four species due to reproductive isolation due to geological changes. This isolation occurred 25,000 years ago. Due to the short isolation time , these are not completely species. According to different ecological characteristics, Yunnan snub-nosed monkeys that survive at high altitudes are called evolutionarily advanced species, while Vietnamese snub-nosed monkeys are relatively primitive, Sichuan snub-nosed monkeys and Guizhou snub-nosed monkeys are closely related, and Guizhou snub-nosed monkeys are relatively primitive.