How primate mothers interact with their dead infants has attracted much attention from primatologists. In particular, the care given to infant corpses has been well documented, and some researchers have employed quantitative analyses to explore the underlying mechanisms of this behavior. In contrast, instances of maternal cannibalism, another striking response to dead infants, are relatively uncommon and the factors contributing to this phenomenon remain unclear among primates. Here, we report a new case of stillbirth and subsequent maternal cannibalism that occurred in a free-ranging group of Japanese macaques residing on Awajishima Island, Japan. In the observed case, a multiparous female gave a stillbirth in the winter of 2022. The newborn appeared premature due to the lack of hair and unformed limbs, and the unseasonal birth. Initially, the mother cared for the newborn by licking and holding the body, but she suddenly began consuming the entire corpse, except for the parts around the head. This is the first case of maternal cannibalism by a multiparous mother of free-ranging Japanese macaque. We compared this case with those previously reported in Old World monkeys, and discussed the possible link between stillbirth, maternal care, and cannibalization towards deceased infants. In order to understand how primates comprehend the concepts of “death” and how their maternal relationships have evolved, it would be important to focus not only on maternal care toward dead infants but also cannibalism that could occur at the end of the caregiving.

灵长类动物母亲如何与死去的婴儿互动，引起了灵长类动物学家的广泛关注。特别是，对婴儿尸体的护理已有详细记录，一些研究人员已经采用定量分析来探索这种行为的潜在机制。相比之下，母体同类相食的情况相对较少，这是对死去婴儿的另一种显着反应，而且在灵长类动物中导致这种现象的因素仍不清楚。在这里，我们报告了一个新的死产和随后的同类相食的病例，该病例发生在日本淡路岛的一群自由放养的日本猕猴身上。在观察的病例中，一名经产女性在2022年冬季产下死产。新生儿由于毛发缺乏、四肢未成形以及非季节性分娩而显得早产。最初，母亲通过舔舐和抱着婴儿的尸体来照顾新生儿，但她突然开始吞噬整个尸体，除了头部周围的部分。这是首例散养日本猕猴的多产母亲同类相食的案例。我们将此病例与之前报道的旧世界猴子病例进行了比较，并讨论了死产、产妇护理和同类相食之间可能存在的联系。为了了解灵长类动物如何理解“死亡”的概念以及它们的母性关系如何演变，重要的是不仅要关注对死亡婴儿的母性护理，还要关注护理结束时可能发生的同类相食行为。