Two neighbors of mine were hunting in the woods when they came upon a weasel chasing a red squirrel around the trunk of a big oak; round and round they went in a fury of flight and pursuit. The men stood and looked on. It soon became apparent that the weasel was going to get the squirrel, so they watched their chance and shot the bloodsucker. Why the squirrel did not take to the tree-tops, where the weasel probably would not have followed him, and thus make his escape—who knows? One of my neighbors, however, says he has seen where a weasel went up a tree and took a gray squirrel out of its nest and dropped it on the snow, then dragged it to cover and left it dead. The weasel seems to inspire such terror in its victim that it becomes fairly paralyzed and falls an easy prey. Those cruel, blazing, beadlike eyes, that gliding snakelike form, that fearless, fatelike pursuit and tenacity of purpose, all put a spell upon the pursued that soon renders it helpless. A weasel once pursued a hen to my very feet and seized it and would not let it go until I put my foot upon it and gripped it by the back of the neck with my hand. Its methods are a kind of Schrecklichkeit in the animal world. It is the incarnation of the devil among our lesser animals.
X. MISINTERPRETING NATURE
We are bound to misinterpret Nature if we start with the assumption that her methods are at all like our methods. We pick out our favorites among plants and animals, those that best suit our purposes. If we want wool from the sheep, we select the best-fleeced animals to breed from. If we want mutton, we act accordingly. If we want cows for quantity of milk, irrespective of quality, we select with that end in view; if we want butter-fat, we breed for that end, and so on. With our fruits and grains and vegetables we follow the same course. We go straight to our object with as little waste and delay as possible.
Not so with Nature. She is only solicitous of those qualities in her fruits and grains which best enable them to survive. In like manner she subordinates her wool and fur and milk to the same general purpose. Her one end is to increase and multiply. In a herd of wild cattle there will be no great milchers. In a band of mountain sheep there will be no prize fleeces. The wild fowl do not lay eggs for market.
Those powers and qualities are dominant in the wild creatures that are necessary for the survival of the species—strength, speed, sharpness of eye and ear, keenness of scent; all wait upon their survival value.
Our hawks could not survive without wing-power or great speed, but the crow survives without this power, because he is an omnivorous feeder and can thrive where the hawk would starve, and also because no bird of prey wants him, and, more than that, because he is dependent upon nothing that requires speed to secure. He is cunning and suspicious for reasons that are not obvious. The fox in this country requires both speed and cunning, but in South America Darwin saw a fox so indifferent and unafraid that he walked up to it and killed it with his geologist's hammer. Has it no enemies in that country?
Nature's course is always a roundabout one. Our petty economies are no concern of hers. Man wants specific results at once. Nature works slowly to general results. Her army is drilled only in battle. Her tools grow sharper in the using. The strength of her species is the strength of the obstacles they overcome. We misinterpret Darwin when we assume that Nature selects as man selects. Nature selects solely upon the principle of power of survival. Man selects upon the principle of utility. He wants some particular good—a race-horse, a draft-horse—better quality or greater quantity of this or that. Nature aims to fill the world with her progeny. Only power to win in the competition of life counts with her. As I have so often said, she plays one hand against the other. The stakes are hers whichever wins. Wheat and tares are all one to her. She pits one species of plant or animal against another—heads I win, tails you lose. Some plants spread both by seed and runners, this doubles their chances; they are kept in check because certain localities are unfavorable to them. I know a section of the country where a species of mint has completely usurped the pastures. It makes good bee pasturage, but poor cattle pasturage. Quack grass will run out other grass because it travels under ground in the root as well as above ground in the seed.
XI. NATURAL SCULPTURE
We may say that all the forms in the non-living world come by chance, or by the action of the undirected irrational physical forces, mechanical or mechanico-chemical. There are not two kinds of forces shaping the earth's surface, but the same forces are doing two kinds of work, piling up and pulling down—aggregating and accumulating, and separating and disintegrating.
It is to me an interesting fact that the striking and beautiful forms in inorganic nature are not as a rule the result of a building-up process, but of a pulling-down or degradation process. A natural bridge, an obelisk, caves, canals, the profile in the rocks, the architectural and monumental rock forms, such as those in the Grand Cañon and in the Garden of the Gods, are all the result of erosion. Water and other aerial forces are the builders and sculptors, and the nature and structure of the material determine the form. It is as if these striking forms were inherent in the rocks, waiting for the erosive forces to liberate them. The stratified rocks out of which they are carved were not laid down in forms that appeal to us, but layer upon layer, like the leaves of a book; neither has the crumpling and deformation of the earth's crust piled them up and folded them in a manner artistic and suggestive. Yet behold what the invisible workmen have carved out of them in the Grand Cañon! It looks as though titanic architects and sculptors had been busy here for ages. But only little grains of sand and a vast multitude of little drops of water, active through geologic ages, were the agents that wrought this stupendous spectacle. If the river could have builded something equally grand and beautiful with the material it took out of this chasm! But it could not—poetry at one end of the series and dull prose at the other. The deposition took the form of broad, featureless, uninteresting plains—material for a new series of stratified rocks, out of which other future Grand Cañons may be carved. Thus the gods of erosion are the artists, while the builders of the mountains are only ordinary workmen.