蛇在爬行时常一伸一缩地探出前端分叉的长舌。它在干什么呢?原来蛇是近视眼，眼力并不好。但它的舌头特别灵敏，能“闻”气味。蛇一边爬行，一边吐舌头，实际上是在边走边搜寻猎物。如果发现鸟、青蛙、老鼠、野兔等一些小动物，它会立即扑过去，把口张得很大很大，把它们囫囵吞 As the snake crawls, it often stretches out the long tongue at the front end. What is it doing? The snake was myopic and its eyesight was not good. But its tongue is particularly sensitive and can “smell” the smell. While crawling, the snake sticks its tongue and is actually searching for prey while walking. If some small animals such as birds, frogs, mice, hares, etc. are found, they will immediately rush over and open their mouths very large and devour them.