The classic essay on this topic is "On Being the Right Size" by biologist J.B.S. Haldane in 1926. It's really worth a read: http://irl.cs.ucla.edu/papers/right

The classic essay on this topic is "On Being the Right Size" by biologist J.B.S. Haldane in 1926. It's really worth a read: http://irl.cs.ucla.edu/papers/right-size.html http://irl.cs.ucla.edu/papers/right-size.html I'll never forget: "You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom, it gets a slight shock and walks away, provided that the ground is fairly soft. A rat is killed, a man is broken, a horse splashes."