科学家发现,蛇的行走千姿百态,有时直线行走,有时蜿蜒曲折而前进。蛇之所以能爬行,在于它有三种特殊的运动方式。第一种为蜿蜒运动,所有的蛇都能以这种方式向前爬行。蛇体爬行时在地面上作水平波状弯曲,使弯曲处的后边施力于粗糙的地面上,由地面的反作用力推动蛇体前进。第二种是履带式运动,这是由于蛇的结构所决定的。虽然蛇体没有胸骨,但是肋骨可以前后自由移动,靠肋皮肌把肋骨与腹鳞相连起来。当肋皮肌收缩时,肋骨便向前移动,这就带动宽大的腹鳞依次竖立,好像踩着地 Scientists found that the snake’s walking varied, sometimes straight, and sometimes twists and turns and progress. The reason why a snake can crawl is that it has three special ways of exercising. The first is a meandering movement, and all the snakes can crawl forward in this manner. Snake crawling on the ground for horizontal wavy bending, so that behind the bend at the rough surface of the ground, by the reaction of the ground to promote snake body forward. The second is crawler motion, which is due to the structure of the snake. Although the snake body does not have a sternum, the ribs can move freely back and forth, connecting the ribs to the abdominal scales by the ribs. When the costal muscle contraction, the ribs will move forward, which led to the large abdominal scales were erected, as if stepping on