Birth is a fundamental event in the lives of animals, including our own species. In order to better understand the evolutionary pressures shaping birthing behaviors in our lineage, more reports of births and stillbirths in wild-living non-human primates are needed. In diurnal non-human primates, births generally occur at night, when individuals are at rest. Consequently, they are difficult to observe in the wild, and most current knowledge of perinatal behavior comes from rare daytime births. Information on stillbirths is even rarer, and their immediate causes are generally unknown.
In this study, we present detailed observations of a daytime birth of a stillborn wild mandrill (Mandrillus sphinx). During this event, which lasted a full day, we recorded the behaviors of the parturient female ad libitum, using video recordings and photographs. The 5-year-old female was primiparous and occupied a low dominance rank. The duration of her pregnancy was shorter than normal, and the parturition phase was extremely long compared with other reports of births in non-human primates. The female disappeared shortly after this event and was assumed to have died. We discuss the possible causes of this stillbirth, including the infant's presentation at birth and maternal inexperience.
