Daytime birth and postbirth behavior of wild Rhinopithecus roxellana in the Qinling Mountains of China.

Reports and quantitative descriptions of wild primate births are rare due to the frequent occurrence of nighttime parturitions. The aim of this study was to describe in detail one daytime birth event in a free-ranging band of Sichuan snub-nosed monkeys (Rhinopithecus roxellana), a highly endangered colobine species endemic to China. Using focal-animal sampling, we recorded both the birth event and behavior of the mother and other group members. The partum stage lasted 4 min 10 s. Immediately after parturition, the mother severed the umbilical cord, ingested the placenta, and cleaned the newborn. During the birthing process, the mother received what may possibly be described as birth assistance from one multiparous female within the same one-male unit. Although "aunting" or infant caregiving behavior has previously been reported in coloblines, this is the first putative case of birth assistance in a nonhuman primate.