抄録
To understand social organizations of the Sichuan snub-nosed monkey, we studied a free ranging band in their natural habitats from 2001 to 2007. The study confirmed this species live in a multi-level social aggregation. One-male unit, on average 1 male, 4 females and youngsters, is their basic social unit. The band, a higher social structure, comprised of 4 to 8 one-male units that consistently carried out their activities together. Adult females placed high priority of long-term relationships with other females in the one-male units, while adult male were socially peripheral. Among one-male units, clear dominance relationships existed, and the dominance ranks were stable for years. Dominance ranks of one-male units positively correlated with unit sizes and the duration of their stay in the band. I discussed possible evolutionary factors of their multi-level societies, by comparing with several other primate species living in multi-level societies, e.g. Gelada baboon, Hamadryas baboon and Proboscis monkey.
