A mouse can fall down a mine shaft a third of a mile deep without injury. A rat falling the same distance would break his bones; a man would simply splash ... Elephants have their legs thickened to an extent that seems disproportionate to us, but this is necessary if their unwieldy bulk is to be moved at all ... A 60-ft. man would weigh 1000 times as much as a normal man, but his thigh bone would have its area increased by only 100 times ... Consequently such an unfortunate monster would break his legs the moment he tried to

John Scott Haldane