DISSERTATION RESEARCH: Comparative Biomechanics of Sand Locomotion in Lizards

论文研究：蜥蜴沙运动的比较生物力学怀亚特·L·科夫·马瓦利·H·韦克加州大学伯克利分校许多动物都生活在风沙上。鉴于此，令人惊讶的是，人们对动物身体形态中可能有助于在沙子上行走的元素知之甚少。就像雪地鞋帮助人类在雪地上行走一样，之前的研究表明，拥有脚趾边缘(侧面突出的细长鳞片)的蜥蜴适合在沙子上跑步，但这一假设尚未得到严格的检验。在这项研究中，研究人员将研究三种密切相关的沙居蜥蜴的快速奔跑：莫哈韦条纹脚趾蜥蜴(Uma Scorparia)，以及斑马尾蜥蜴的非条纹加州蜥蜴(Callisaurus Draconoides Draconoids)和边缘墨西哥蜥蜴(Callisaurus Draconoides Crtis)亚群。这项工作将解决两个一般性问题：1.蜥蜴脚趾上的流苏是否有助于它们在沙子上奔跑？2.脚的形状变化如何影响力从动物到沙质底物的传递？这项工作通过综合生物生物学、进化生物学、机械工程和颗粒物理等领域来解决这些问题。研究人员将使用能够每秒记录1000张图像的摄像机(标准摄像机每秒记录30张图像)来减缓动物在自然环境中的运动，因为它们在许多不同的底物上运行。收集到的信息将被用来建造一个机器人附属物，在这个附属物上将附着代表在许多不同种类蜥蜴身上发现的不同脚型的模型。通过回放机器人控制的脚上现场记录的运动模式，研究人员将能够测量不同脚形通过蜥蜴居住的底物产生的力。从这些研究中，可以直接测量脚的形状变化对推动动物前进的影响。这项工作是第一次研究动物如何在不同的底物上奔跑，以及是否有特定的脚型可能更有效地在沙子上快速移动。

Dissertation Research: Comparative biomechanics of sand locomotion in lizardsWyatt L. KorffMarvalee H. WakeUniversity of California, Berkeley Many animals spend their lives on fine wind-blown sand. Given this, it is surprising that so little is known about the elements of an animal's body form that may aid in locomotion over sand. Much like snowshoes aid humans moving on snow, previous investigations have suggested that lizards that possess toe fringes (sideways projecting elongate scales) are adapted to running on sand, but this hypothesis has yet to be rigorously tested. In this study, the investigators will study the rapid running of three closely related sand dwelling lizards: the Mojave fringe-toed lizard (Uma scorparia), and non-fringed California (Callisaurus draconoides draconoides) and fringed Mexican (Callisaurus draconoides crinitis) subpopulations of the zebra-tailed lizard. Two general questions will be addressed in this work: 1. do fringes on the toes of lizards help them run on sand? and 2. how does variation in foot shape affect the transmission of forces from the animal to the sandy substrate? This work approaches these questions by synthesizing the fields of organismal biology, evolutionary biology, mechanical engineering, and granular physics. The researchers will use video cameras capable of recording 1000 images per second (standard cameras record at 30 images per second) to slow down the movement of animals in their natural environments as they run on a number of different substrates. Information gathered will be used to construct a robotic appendage to which models representing the diversity of foot shapes found in many different species of lizards will be attached. By "playing back" the movement patterns recorded in the field on the robotically controlled feet, the investigators will be able to measure the forces generated by different foot shapes through substrates where the lizards live. From these studies, the effect of changes in foot shape in propelling the animals forward can be directly measured. This work is one of the first to investigate how animals run on different substrates, and whether there are particular foot shapes that may be more effective for rapid movements on sand.