南美洲的哥斯达黎加雨林里,有一种以蛙为食的蛇。由于那里的蛙非常多,所以自古以来,这种蛇从来不必为食物担忧。可是近几年,细心的科学家们发现,这种蛇有时也会面临食物危机。因为蛙的进化远比蛇快。进化让蛙有了逃脱蛇口的本领。它们不但进化出更加敏锐的眼睛、更加有力的四肢,并且可以在水面上奔跑。当一条蛇试图靠近一只蛙时,这只蛙便会奋力跳开,然后像武 In the Costa Rican rain forest of South America, there is a snake that feeds on frogs. Since there are so many frogs, the snake has never had to worry about food since ancient times. But in recent years, attentive scientists have found that such snakes sometimes face a food crisis. Because frogs evolved far faster than snakes. Evolution has given frogs the ability to escape Shekou. They not only evolve more sharp eyes, more powerful limbs, and can run on the water. When a snake tries to get closer to a frog, the frog strives to jump off, then like a weapon