Snakes mimic earthworms: propulsion using rectilinear travelling waves
Snakes mimic earthworms: propulsion using rectilinear travelling waves
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DOI：
10.1098/rsif.2013.0188
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发表时间：
2013-07-06
影响因子：
3.9
通讯作者：
Hu, David L.
中科院分区：
文献类型：
--
作者：
Marvi, Hamidreza;Bridges, Jacob;Hu, David L.
在直线运动中，蛇利用肌肉收缩的单向行波推动自己，其方式类似于蚯蚓。在这项实验和理论相结合的研究中，我们拍摄了三种蛇的直线运动，包括红尾蟒蛇，杜梅里尔的蟒蛇和加蓬毒蛇。蛇伸缩行波的运动学特征是波的频率、振幅和速度。我们发现波的频率随着身体尺寸的增加而增加，这与有腿动物的趋势相反。我们预测身体的速度与73-97%的准确性使用的数学模型的一维n连接的履带车，使用摩擦力作为主要的推进力。我们应用我们的模型来显示蛇有最佳的波频率：较高的值增加弗劳德数，导致蛇滑动;较小的值减少推力，所以身体的速度。运动学变量的其他选择，如波振幅，是次优的，似乎受到解剖约束。我们的模型还显示，局部身体提升使蛇的速度增加了31%，这表明直线运动受益于类似于步行的垂直运动。
In rectilinear locomotion, snakes propel themselves using unidirectional travelling waves of muscular contraction, in a style similar to earthworms. In this combined experimental and theoretical study, we film rectilinear locomotion of three species of snakes, including red-tailed boa constrictors, Dumeril's boas and Gaboon vipers. The kinematics of a snake's extension-contraction travelling wave are characterized by wave frequency, amplitude and speed. We find wave frequency increases with increasing body size, an opposite trend than that for legged animals. We predict body speed with 73-97% accuracy using a mathematical model of a one-dimensional n-linked crawler that uses friction as the dominant propulsive force. We apply our model to show snakes have optimal wave frequencies: higher values increase Froude number causing the snake to slip; smaller values decrease thrust and so body speed. Other choices of kinematic variables, such as wave amplitude, are suboptimal and appear to be limited by anatomical constraints. Our model also shows that local body lifting increases a snake's speed by 31 per cent, demonstrating that rectilinear locomotion benefits from vertical motion similar to walking.