Locomotor benefits of being a slender and slick sand-swimmer
Locomotor benefits of being a slender and slick sand-swimmer
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苗条、光滑的沙泳者的运动优势
DOI：
10.1242/jeb.121939
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Daniel I. Goldman
中科院分区：
文献类型：
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作者：
Sarah S. Sharpe;Stephan A. Koehler;Robyn Kuckuk;M. Serrano;Patricio A. Vela;Mendelson J rd;Daniel I. Goldman
被归类为“亚砂质”的有鳞动物具有在干沙中长距离移动的能力;沙和土壤穴居者之间的身体伸长被假设为提高地下性能。使用X射线成像，我们进行了第一次运动学调查的地下运动的长，细长的铲鼻蛇（Chionactis occipitalis），并比较其生物力学与较短的，四肢沙鱼蜥蜴（Scincus scincus）。以前的研究表明，沙鱼可以最大限度地提高游泳速度，并最大限度地减少埋葬过程中的机械运输成本。我们的测量结果显示，蛇也通过传播行波下的身体，头到尾游过沙子。与沙鱼不同的是，这条蛇几乎是沿着自己的轨迹前进，因此它在一个近似于自流化颗粒介质的管道中游动。我们通过引入局部滑移角βs参数来测量管运动的偏差，βs测量每个节段的运动方向与身体取向之间的角度。蛇的平均βs小于沙鱼;颗粒阻力理论（RFT）表明，每种动物利用的曲率优化了其性能。蛇受益于其细长的身体形状（和增加的椎骨数量），这允许传播更高数量的最佳曲率身体波动。蛇的低表面摩擦也提高了性能。实验和RFT之间的协议相结合的颗粒状的“摩擦流体”的相对简单的性能，使subarsenaceous游泳一个有吸引力的系统来研究功能形态和包平面演化。
Squamates classified as ‘subarenaceous’ possess the ability to move long distances within dry sand; body elongation among sand and soil burrowers has been hypothesized to enhance subsurface performance. Using X-ray imaging, we performed the first kinematic investigation of the subsurface locomotion of the long, slender shovel-nosed snake (Chionactis occipitalis) and compared its biomechanics with those of the shorter, limbed sandfish lizard (Scincus scincus). The sandfish was previously shown to maximize swimming speed and minimize the mechanical cost of transport during burial. Our measurements revealed that the snake also swims through sand by propagating traveling waves down the body, head to tail. Unlike the sandfish, the snake nearly followed its own tracks, thus swimming in an approximate tube of self-fluidized granular media. We measured deviations from tube movement by introducing a parameter, the local slip angle, βs, which measures the angle between the direction of movement of each segment and body orientation. The average βs was smaller for the snake than for the sandfish; granular resistive force theory (RFT) revealed that the curvature utilized by each animal optimized its performance. The snake benefits from its slender body shape (and increased vertebral number), which allows propagation of a higher number of optimal curvature body undulations. The snake’s low skin friction also increases performance. The agreement between experiment and RFT combined with the relatively simple properties of the granular ‘frictional fluid’ make subarenaceous swimming an attractive system to study functional morphology and bauplan evolution.