其实蛇的祖先也是有脚的,今天我们之所以看不到它的脚,是因为它们慢慢退化了。现在的蛇爬行主要靠腹鳞,在它腹面中央,较大而呈长方形。需要移动时,腹鳞稍稍翘起,翘起的鳞片尖端象脚一样踩住地面或其他物体,推动蛇的身体前进。另外,蛇的椎骨前端还有两个椎弓突,与前一椎骨后端的椎弓凹构成关节,也增加了蛇身左 In fact, the snake’s ancestors also have feet, and today we can not see its feet, because they slowly degenerated. Snake crawling now mainly rely on abdominal scales, in its ventral center, larger and rectangular. When you need to move, the ventral scales slightly tilt, tilt the tip of the scales as the foot treading the ground or other objects, to promote the snake’s body forward. In addition, the vertebrae of the snake also has two vertebral arches, forming a joint with the vertebral arch of the anterior vertebra of the anterior vertebra,