Parturitions in Wild White-Headed Langurs (Trachypithecus leucocephalus) in the Nongguan Hills, China

There are few detailed descriptions of parturition behavior in wild primates. Here we report for the first time birth-related behaviors in a highly endangered colobine monkey endemic to southwest China, the white-headed langur (Trachypithecus leucocephalus). We video recorded three complete birth events in three parturient females living in one reproductive group. The births occurred during the night at one of the group's sleeping sites. One parturient was primiparous, while the other two were multiparous. All three delivered close to other group members. Common behaviors among the parturients included adopting a raised-rump posture during contractions, manual inspection of the anogenital area followed by hand-licking, manual self-assistance as the infant emerged, holding and licking the infant immediately after the birth, and ingesting the placenta. However, we found considerable individual variation in birth-related behaviors. The primiparous female had the longest prepartum phase and more contractions than the two multiparous females. All three mothers ingested the placenta, but the primipare took much longer than the two multiparous mothers to deliver the placenta, start to ingest it, and consume it. Other group members had little interaction with the parturients during the prepartum phase, but showed intense interest in the neonates. The newly born infants were held by nonmaternal adult females of the group within 5-9 h of their birth. Our case studies stress the importance of the social context at parturition in group-living primates, and suggest that parity of parturients may influence birth-related behavior.