时差N小时 为什么马的腿很细?(下)（在线收听）

Then that foot stops and the other one accelerates. And so on. Thinner, lighter things are easier to accelerate than heavy, massive ones. So if you want speed, put the muscles up high and the skinny down low. Speed If you really want speed, you could go even further and pare down the foot, to decrease lower leg mass even more. A few million years of evolution and you’ll wind up with…you guessed it. A hoof.

然后，一只脚停下来，另一只脚加速。依此类推。更细、更轻的东西比重的、体积大的东西加速快。所以如果你想要速度，上半身肌肉要多些，而下半身要瘦些。想要速度时就加速，你可以走得更远。缩减脚的尺寸，减少小腿的重量。几百万年的进化后，你会停止……你猜对了。进化成一个蹄。