Abstract: The social systems of primates are highly diverse, but their evolutionary history, especially the origin of some most complex societies, remains elusive. Although much attention has been focused on this issue for about one century and tremendous progress has been made in the fields of social ecology and ethology, we still know little about the genetic underpinnings of primates’ social behaviors. Recently, a joint team of Chinese and foreign scientists, led by Professor Qi Xiaoguang of Northwest University, has provided new insights into this question with evidence from comparative genomics, ecology, paleontology, ethology, and cell biology. This work has been published in Science. They focused on the natural history of Asian colobines, a group of unique and endangered Old World monkeys, and discovered the possible driving force of their social evolution. The results demonstrated that this taxon’s social systems both have a strong phylogenetic signal and were deeply affected by historical environmental events. Rapid evolution and reorganization of dopamine and oxytocin pathways driven by cold climate may play a key role in the formation of the most complex multi-level societies. This study has pioneered a “behavior-ecology-genome” paradigm, opening up a new avenue for the study of primate social evolution.