Department of Anthropology, University of Florida, Room 1112, Turlington Hall, Gainesville, FL 32611-7305, 117305, USA.
Department of Anthropology, The Ohio State University, Columbus, OH, USA.
Primates. 2021 Mar;62(2):361-367. doi: 10.1007/s10329-020-00863-w. Epub 2020 Sep 22.
The sooty mangabey (Cercocebus atys) practices year-round durophagy. A large part of the C. atys diet consists of the oily nut of Sacoglottis gabonensis, which is accessed by post-canine crushing of the hard, protective seed coat. During a typical foraging bout, some seeds are discarded after initial crushing attempts using isometric biting, but the reason mangabeys reject some seeds and break into others is unclear. Although C. atys is sexually dimorphic, little is known about whether differences between males and females affect the selectivity of mechanically protected foods. We studied C. atys feeding on S. gabonensis in the Taï National Park, Côte d'Ivoire, in July and August 2016. Nuts discarded after an initial crushing attempt were collected and their hardness measured using a Shore D durometer. Measurements were taken in the region of the nut where monkeys attempted to crush it. Hardness values of nuts rejected by adult male (n = 79) and adult female (n = 104) C. atys were compared to those of a control assemblage of nuts collected randomly on the forest floor (n = 69). Nuts rejected by either sex do not differ statistically from the random sample; however, they do differ from each other, with females rejecting harder nuts. This suggests that males are more effective at broaching harder seed husks, and discard seeds based on other factors.
黑长尾猴（Cercocebus atys）全年都在进行硬性食物摄食。黑长尾猴的饮食很大一部分由 Sacoglottis gabonensis 的油性坚果组成，这种坚果的坚硬保护壳可以通过后犬齿的挤压来获取。在典型的觅食过程中，一些种子在使用等长咬合进行初步破碎尝试后被丢弃，但黑长尾猴拒绝某些种子并打破其他种子的原因尚不清楚。尽管 C. atys 存在性别二态性，但对于雄性和雌性之间的差异是否会影响对机械保护食物的选择性知之甚少。我们在 2016 年 7 月和 8 月在科特迪瓦的泰国家公园研究了 C. atys 对 S. gabonensis 的摄食情况。在最初的破碎尝试后丢弃的坚果被收集起来，并使用 Shore D 硬度计测量其硬度。测量是在猴子试图破碎坚果的区域进行的。成年雄性（n=79）和成年雌性（n=104）C. atys 拒绝的坚果的硬度值与在森林地面上随机收集的坚果的控制样本（n=69）进行了比较。无论是雄性还是雌性拒绝的坚果在统计学上都与随机样本没有差异；然而，它们彼此之间存在差异，雌性拒绝更硬的坚果。这表明雄性在破开更硬的种皮方面更有效，并根据其他因素丢弃种子。
