Andrada Emanuel, Haase Daniel, Sutedja Yefta, Nyakatura John A, Kilbourne Brandon M, Denzler Joachim, Fischer Martin S, Blickhan Reinhard
Science of Motion, Friedrich-Schiller University of Jena, Germany.
Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum, Friedrich-Schiller University of Jena, Germany.
Sci Rep. 2015 Sep 3;5:13636. doi: 10.1038/srep13636.
Scientists have historically categorized gaits discretely (e.g. regular gaits such as walking, running). However, previous results suggest that animals such as birds might mix or regularly or stochastically switch between gaits while maintaining a steady locomotor speed. Here, we combined a novel and completely automated large-scale study (over one million frames) on motions of the center of mass in several bird species (quail, oystercatcher, northern lapwing, pigeon, and avocet) with numerical simulations. The birds studied do not strictly prefer walking mechanics at lower speeds or running mechanics at higher speeds. Moreover, our results clearly display that the birds in our study employ mixed gaits (such as one step walking followed by one step using running mechanics) more often than walking and, surprisingly, maybe as often as grounded running. Using a bio-inspired model based on parameters obtained from real quails, we found two types of stable mixed gaits. In the first, both legs exhibit different gait mechanics, whereas in the second, legs gradually alternate from one gait mechanics into the other. Interestingly, mixed gaits parameters mostly overlap those of grounded running. Thus, perturbations or changes in the state induce a switch from grounded running to mixed gaits or vice versa.
从历史上看，科学家们将步态进行了离散分类（例如行走、奔跑等常规步态）。然而，先前的研究结果表明，像鸟类这样的动物在保持稳定运动速度的同时，可能会混合或有规律地、随机地在不同步态之间切换。在这里，我们将一项关于几种鸟类（鹌鹑、蛎鹬、北方麦鸡、鸽子和反嘴鹬）质心运动的新颖且完全自动化的大规模研究（超过一百万个帧）与数值模拟相结合。所研究的鸟类在较低速度时并不严格偏好行走机制，在较高速度时也不严格偏好奔跑机制。此外，我们的研究结果清楚地表明，我们研究中的鸟类采用混合步态（例如一步行走接着一步采用奔跑机制）的频率高于行走，而且令人惊讶的是，可能与地面奔跑的频率一样高。使用基于从实际鹌鹑获得的参数的仿生模型，我们发现了两种类型的稳定混合步态。在第一种类型中，双腿表现出不同的步态机制，而在第二种类型中，双腿逐渐从一种步态机制转换为另一种步态机制。有趣的是，混合步态的参数大多与地面奔跑的参数重叠。因此，状态的扰动或变化会导致从地面奔跑切换到混合步态，反之亦然。
