A paper published in the journal Behavioural Processes describes a rare phenomenon, midwifery behavior among black snub-nosed monkeys in Yunnan, China. The paper is titled, “Daytime birth and parturition assistant behavior in wild black-and-white snub-nosed monkeys (Rhinopithecus bieti) Yunnan,China,” and documents this day time birth accompanied by a helper.
As you may know, primates have a large head to body ratio — larger than other mammals. This makes birthing a challenge as larger head has to pass through the birth canal. As a result, labor is far more laborious and risky and primate infants are born less developed than other mammals.
Assistance during labor has been seen a few time before. In one case, a male cottontop tamarin pulled his infant’s shoulders. Another report documents the grooming of a female capped langur during birth, perhaps in trying to ease the distress. While primates offer some help during birth, it has been seen in that male Djungarian hamsters regularly assist with deliveries, pulling infants out with their front paws and incisors.
In the paper, Xiao and colleague document the 15 minute birthing of a first time mother. She climbs up a rhododendron tree, faintly calling. Her calls turn into screams within 10 minutes. An experienced female black snub-nosed monkey climbs up to this screaming mother. As the new mother began crowning, the experienced female sat beside.
The head, once fully exposed, was grabbed by the midwife, who pulled the baby out with both hands. She progressed to rip open the birth membranes. The new mother reclaimed the infant within a minute, and severed the umbilical cord. She ate the placenta as the midwife descended.
Black snub-nosed monkeys live in bands. These bands are as large as 300-400, but are often sub-divided into smaller groups of 10 individuals. These groups are often harems. The female black snub-nosed monkeys tend to stay in the group they were born in. It is likely, therefore, that females in a group are closely related and to have strong social bonds and act upon calledkin selection. Furthermore, it has been observed that juvenile females closely watching births. During this particular birth, two other females watched it happen.
Ding, W., Yang, L., & Xiao, W. (2013). Daytime birth and parturition assistant behavior in wild black-and-white snub-nosed monkeys (Rhinopithecus bieti) Yunnan,China Behavioural Processes DOI: 10.1016/j.beproc.2013.01.006