Schmitt Daniel, Hanna Jandy B
Department of Biological Anthropology and Anatomy, Duke University Medical Center, Box 3170, Durham, NC 27710, USA.
J Hum Evol. 2004 Mar;46(3):239-54. doi: 10.1016/j.jhevol.2003.11.008.
It is often claimed that the walking gaits of primates are unusual because, unlike most other mammals, primates appear to have higher vertical peak ground reaction forces on their hindlimbs than on their forelimbs. Many researchers have argued that this pattern of ground reaction force distribution is part of a general adaptation to arboreal locomotion. This argument is frequently used to support models of primate locomotor evolution. Unfortunately, little is known about the force distribution patterns of primates walking on arboreal supports, nor do we completely understand the mechanisms that regulate weight distribution in primates. We collected vertical peak force data for seven species of primates walking quadrupedally on instrumented terrestrial and arboreal supports. Our results show that, when walking on arboreal vs. terrestrial substrates, primates generally have lower vertical peak forces on both limbs but the difference is most extreme for the forelimb. We found that force reduction occurs primarily by decreasing forelimb and, to a lesser extent, hindlimb stiffness. As a result, on arboreal supports, primates experience significantly greater functional differentiation of the forelimb and hindlimb than on the ground. These data support long-standing theories that arboreal locomotion was a critical factor in the differentiation of the forelimbs and hindlimbs in primates. This change in functional role of the forelimb may have played a critical role in the origin of primates and facilitated the evolution of more specialized locomotor behaviors.
人们常说灵长类动物的行走步态与众不同,因为与大多数其他哺乳动物不同,灵长类动物后肢的垂直地面反作用力峰值似乎高于前肢。许多研究人员认为,这种地面反作用力分布模式是对树栖运动的一种普遍适应的一部分。这一观点经常被用来支持灵长类动物运动进化模型。不幸的是,对于灵长类动物在树栖支撑物上行走时的力分布模式知之甚少,而且我们也不完全了解调节灵长类动物体重分布的机制。我们收集了七种灵长类动物在装有仪器的陆地和树栖支撑物上四足行走时的垂直峰值力数据。我们的结果表明,当在树栖与陆地基质上行走时,灵长类动物四肢的垂直峰值力通常较低,但前肢的差异最为显著。我们发现,力的降低主要是通过降低前肢以及在较小程度上降低后肢的刚度来实现的。因此,在树栖支撑物上,灵长类动物前肢和后肢的功能分化比在地面上显著更大。这些数据支持了长期以来的理论,即树栖运动是灵长类动物前肢和后肢分化中的一个关键因素。前肢功能作用的这种变化可能在灵长类动物的起源中起到了关键作用,并促进了更专门化运动行为的进化。