XLVII
How The Animals Keep Their Tools Sharp
One can not do much of anything without tools, so of course the animals have to have them. But because they haven’t sense enough to make tools as we do, or even sense enough to use such tools as they find ready made—pointed sticks and sharp stones and shells and bits of bone and the like—as our very savage and very stupid ancestors used to do, the tools of the animals have to grow on them.
The horse’s front teeth are his mowing machine, with which he cuts down the grass. His great flat-topped grinding teeth that lie in a long straight row along each side of his jaw behind the place where the bit goes, are his millstones with which he grinds his oats and corn into meal. But the cheek-teeth of dogs and cats, which also lie along the sides of their jaws, are not millstones, but knives; and their front teeth, like their claws, are traps to seize their prey and long daggers to stab them with. For the cats and dogs do not grind corn; they kill things. They are butchers, not millers.
In fact, when you come to think of it, nearly all the larger animals are either millers or butchers. Either they grind up plants for food, as horses and cows and sheep and goats do; or else they hunt and kill other living animals and devour them, as do the cats and dogs and wolves and foxes and hyenas and such like. Naturally, these two sorts of creatures have quite different sorts of tools—claws and sharp teeth for one, hoofs and grinding teeth for the other. Tho for some reason or other, pretty much all the animals that are strong enough to do any work, are miller animals. All the horses, oxen, ponies, donkeys, buffalos, elephants, camels, goats, llamas, and I don’t know how many more, that any body can get any work out of, all have hoofs and eat plants. The Eskimo dog, so far as I know, is the only butcher animal that earns a living. The rest just lie round and growl.
So the miller animals have to grind their food. Now millstones have to be kept rough; and as fast as they wear smooth, the miller has to “pick” out the grooves to make them rough again. In like manner, the horses and cows and sheep would soon wear their teeth too smooth to be of any use, if they did not have a way of making them once more rough. In these grinding, millstone teeth, the hard enamel, instead of being on the outside of the tooth as with us, is doubled into folds and plates, and mixed in with the bone of the tooth like the streak of fat and streak of lean in bacon, or like the two colors in marble cake. So the bone wears down faster than the enamel, and leaves the enamel standing up in sharp ridges. Thus the top of the tooth is always rough and ready to do its grinding; and because these teeth are pretty long, an inch or more, they last a long time before they are worn out.
But the dogs and cats, which have teeth like ours, with the enamel all on the outside, soon wear down their teeth so that they will no longer cut. That’s why dogs and cats and the wild creatures like them, are so short lived. They are built to grow up quickly and die young, because there is no use in having them made to live longer than their teeth will hold out. At least that’s one reason Why they don’t live longer.
The elephants have a curious way of taking care of their teeth. They have to take care of them, because the elephants live to be very old—a hundred years—a hundred and fifty—some people say even two hundred. Now a hundred years is a pretty long time for a tooth to keep on grinding leaves and twigs and roots, so the elephant has to save his teeth and make them last.
To begin with, he saves his front teeth by not having any. His two great tusks are two upper front teeth grown out till they are not teeth at all, but crowbars that the elephant uses to grub up roots with. They have no enamel and no root. So they can keep growing at the inner end as fast as they wear off at the outer. Being especially hard bone, they last as long as the elephant does, and get larger and larger as long as their owner lives. After that, they get turned into piano keys and billiard balls.
As the elephant spares his front teeth by not having any, he spares his back teeth by not having many at a time. These are very large, not quite as large as a leg of ham, but quite as large, often times, as a loaf of bread.