Nishie Hitonaru, Nakamura Michio
Laboratory of Human Evolution Studies, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, 606-8502.
Am J Phys Anthropol. 2018 Jan;165(1):194-199. doi: 10.1002/ajpa.23327. Epub 2017 Oct 6.
This study reports on the first observed case of a wild chimpanzee infant being snatched immediately after delivery and consequently cannibalized by an adult male in the Mahale Mountains, Tanzania. We demonstrate "maternity leave" from long-term data from the Mahale M group and suggest that it functions as a possible counterstrategy of mother chimpanzees against the risk of infanticide soon after delivery.
The subjects of this study were the M group chimpanzees at Mahale Mountains, Tanzania. The case of cannibalism was observed on December 2, 2014. We used the long-term daily attendance record of the M group chimpanzees between 1990 and 2010 to calculate the lengths of "maternity leave," a perinatal period during which a mother chimpanzee tends to hide herself and gives birth alone.
We observed a very rare case of delivery in a wild chimpanzee group. A female chimpanzee gave birth in front of other members, and an adult male snatched and cannibalized the newborn infant immediately after birth. Using the long-term data, we demonstrate that the length of "maternity leave" is longer than that of nonmaternity leave among adult and adolescent female chimpanzees.
We argue that this cannibalism event immediately after birth occurred due to the complete lack of "maternity leave" of the mother chimpanzee of the victim, who might lack enough experience of delivery. We suggest that "maternity leave" taken by expecting mothers may function as a possible counterstrategy against infanticide soon after delivery.
本研究报告了在坦桑尼亚马哈勒山脉首次观察到的一例野生黑猩猩幼崽在出生后立即被成年雄性抢走并吃掉的案例。我们通过马哈勒M群的长期数据展示了“产假”情况,并表明它可能是母黑猩猩应对分娩后不久发生杀婴风险的一种对策。
本研究的对象是坦桑尼亚马哈勒山脉的M群黑猩猩。这起同类相食事件于2014年12月2日被观察到。我们利用1990年至2010年M群黑猩猩的长期每日出勤记录来计算“产假”时长,“产假”是指母黑猩猩倾向于隐藏自己并独自分娩的围产期。
我们在一个野生黑猩猩群体中观察到了一例非常罕见的分娩情况。一只雌性黑猩猩在其他成员面前分娩,一只成年雄性在幼崽出生后立即抢走并吃掉了它。利用长期数据,我们证明成年和青春期雌性黑猩猩的“产假”时长比非产假时长更长。
我们认为出生后立即发生的这起同类相食事件是由于受害者的母黑猩猩完全没有“产假”,而它可能缺乏足够的分娩经验。我们建议准妈妈的“产假”可能是应对分娩后不久杀婴行为的一种可能对策。