Birth in Free-ranging Macaca fuscata

The birth process is an integral part of reproductive success in mammals, yet detailed, quantitative descriptions of parturition in nonhuman primates are still rare. Observations of free-ranging births can help to elucidate factors involved in this critical event, to contribute to our understanding of how maternal and infant behaviors during parturition affect infant survival and to explain the evolution of human birth. We provide data on the parturition behavior of 4 multiparous Japanese macaques: 2 daytime live births that we photographed and video recorded at the Awajishima Monkey Center (AMC), Awaji Island, Japan in 2006; a daytime live birth video recorded in 1993 at the AMC; and a nocturnal breech stillbirth of a captive Macaca fuscata, video recorded at the Kyoto Primate Research Institute in 2006. Certain behaviors were similar among the females, such as touching of the vulva followed by licking of fingers, squatting during contractions, and average contraction durations. Parturient females facilitated the birth manually by guiding the emerging infant. There were also dissimilarities in the duration of the labor and birth stages, condition of the infant at birth, and the mother's behavior immediately postpartum. The mother's postpartum behavior ranged from almost entirely infant-focused to predominantly related to the consumption of the placenta. The 3 free-ranging females all showed considerable social tolerance during labor and birth. We argue that social proximity at parturition is more common in nonhuman primates than previously emphasized, and has potential adaptive advantages.