Hanna Jandy B, Schmitt Daniel, Wright Kristin, Eshchar Yonat, Visalberghi Elisabetta, Fragaszy Dorothy
Division of Biomedical Sciences, 400 N. Lee St., West Virginia School of Osteopathic Medicine, Lewisburg, WV 24901, USA.
Department of Evolutionary Anthropology, 104 Biological Sciences Building, Campus Box 90383, Duke University, Durham, NC 27708, USA.
J Hum Evol. 2015 Aug;85:149-56. doi: 10.1016/j.jhevol.2015.05.006.
Facultative bipedalism during load transport in nonhuman primates has been argued to be an important behavior potentially leading to the evolution of obligate, extended limb bipedalism. Understanding the biomechanics of such behavior may lead to insights about associated morphology, which may translate to interpretation of features in the fossil record. Some populations of bearded capuchin monkeys (Sapajus libidinosus) spontaneously carry heavy loads bipedally during foraging activities. This study provides the first data on all three components of ground reaction force for spontaneous bipedalism during load carriage in a nonhuman primate. Five individual S. libidinosus (mean body mass = 2.4 kg ± 0.96) were videorecorded during bipedalism while carrying a stone (0.93 kg) under natural conditions. A force plate was embedded in the path of the monkeys. Spatiotemporal and force data for all three components of the ground reaction force were recorded for 28 steps. Capuchins exhibited a mean vertical peak force per total weight (Vpk) for the hindlimb of 1.19 (sd = 0.13), consistent with those of unloaded capuchins in the laboratory and for other bipedal primates, including humans. Vertical force records suggest that capuchins, along with most nonhuman primates, maintain a relatively compliant leg during both unloaded and loaded locomotion. Like all other primates, loaded capuchins maintained laterally (outward) directed medio-lateral forces, presumably to stabilize side-to-side movements of the center of mass. Medio-lateral forces suggest that at near-running speeds dynamic stability diminishes the need to generate high lateral forces. Vertical force traces exhibited a measurable impact spike at foot contact in 85% of the steps recorded. An impact spike is common in human walking and running but has not been reported in other bipedal primates. This spike in humans is thought to lead to bone and cartilage damage. The earliest biped may have experienced similar impact spikes during bipedal locomotion, requiring compensatory behaviors or anatomical features.
在非人灵长类动物负重运输过程中的兼性双足行走被认为是一种重要行为，可能导致专性、肢体伸展双足行走的进化。了解这种行为的生物力学可能有助于深入了解相关形态，这可能有助于解释化石记录中的特征。一些有胡须的卷尾猴种群（僧面猴属僧面猴）在觅食活动中会自发地双足背负重物。本研究首次提供了非人灵长类动物负重运输过程中自发双足行走时地面反作用力所有三个分量的数据。五只僧面猴个体（平均体重 = 2.4千克±0.96）在自然条件下双足行走并携带一块石头（0.93千克）时被录像。在猴子的路径中嵌入了一个测力板。记录了28步中地面反作用力所有三个分量的时空和力数据。卷尾猴后肢的平均垂直峰值力与总重量之比（Vpk）为1.19（标准差 = 0.13），与实验室中未负重的卷尾猴以及包括人类在内的其他双足灵长类动物一致。垂直力记录表明，卷尾猴与大多数非人灵长类动物一样，在负重和未负重运动过程中都保持腿部相对柔顺。与所有其他灵长类动物一样，负重的卷尾猴保持侧向（向外）的内侧 - 外侧力，大概是为了稳定质心的左右移动。内侧 - 外侧力表明，在接近奔跑速度时，动态稳定性降低了产生高侧向力的必要性。在记录的85%的步数中，垂直力轨迹在足部接触时出现了可测量的冲击峰值。冲击峰值在人类行走和跑步中很常见，但在其他双足灵长类动物中尚未有报道。人类的这种峰值被认为会导致骨骼和软骨损伤。最早的双足动物在双足行走过程中可能也经历过类似的冲击峰值，这需要补偿行为或解剖特征。
