Sarringhaus Lauren A, MacLatchy Laura M, Mitani John C
Evolutionary Studies Institute, Palaeosciences Centre, University of the Witwatersrand, Johannesburg, South Africa.
University of Maryland University College Europe, PE28 4DE, England.
Am J Phys Anthropol. 2016 May;160(1):16-29. doi: 10.1002/ajpa.22930. Epub 2016 Jan 18.
Recent studies indicate that the locomotor behavior of wild chimpanzees changes during development. Before transitioning to quadrupedal knuckle-walking in adulthood, young chimpanzees engage in a significant amount of upper limb loading suspensory behavior. We investigated whether these dramatic changes in locomotion influence the strength and shape of chimpanzee long bones.
We examined changes in chimpanzee arboreal locomotion over the course of development using behavioral data collected on wild chimpanzees. We measured the midshaft geometric properties of femora and humeri of wild-caught individuals housed in museum collections using micro computed tomographic scans.
Chimpanzees spent less time moving arboreally as they aged. Femoral/humeral strength ratios also increased with age, as predicted by the changing loading environment during development. Additional analyses revealed that femoral shape, but not humeral shape, varied across chimpanzee age classes. Adult femora were more elliptical compared with those of infants. This change in adult femora is consistent with the observation that adult chimpanzees spend most of their time moving terrestrially and consequently experience a less variable loading environment than do infants.
Taken together, these findings contribute to our understanding of how ontogenetic changes in function affect form. As similar changes may have characterized the behavioral and skeletal ontogeny of extinct hominoids including hominins, these findings furnish a potential means to make inferences about the behavior of fossil taxa based on the structural properties of their bones.
近期研究表明，野生黑猩猩的运动行为在发育过程中会发生变化。在成年后过渡到四足指关节行走之前，幼年黑猩猩会进行大量的上肢负重悬垂行为。我们研究了这些运动方式的显著变化是否会影响黑猩猩长骨的强度和形状。
我们利用收集到的野生黑猩猩行为数据，研究了黑猩猩在发育过程中树栖运动的变化。我们使用显微计算机断层扫描测量了博物馆收藏的野生捕获个体的股骨和肱骨骨干中部的几何特性。
随着年龄增长，黑猩猩在树上活动的时间减少。正如发育过程中不断变化的负荷环境所预测的那样，股骨/肱骨强度比也随着年龄增长而增加。进一步分析表明，不同年龄组的黑猩猩股骨形状有所不同，而肱骨形状没有变化。与婴儿的股骨相比，成年黑猩猩的股骨更呈椭圆形。成年黑猩猩股骨的这种变化与以下观察结果一致：成年黑猩猩大部分时间在陆地上活动，因此与婴儿相比，它们所经历的负荷环境变化较小。
综上所述，这些发现有助于我们理解功能的个体发育变化如何影响形态。由于类似的变化可能也表征了包括人类在内的已灭绝类人猿的行为和骨骼个体发育，这些发现为根据化石类群骨骼的结构特性推断其行为提供了一种潜在方法。
