Part 9

The animals all have in varying degrees perceptive intelligence. They know what they see, hear, smell, feel, so far as it concerns them to know it. They know their kind, their mates, their enemies, their food, heat from cold, hard from soft, and a thousand other things that it is important that they should know, and they know these things just as we know them, through their perceptive powers.

We may ascribe intelligence to the animals in the same sense in which we ascribe it to a child, as the perception of the differences or of the likenesses and the relations of things--that is, perceptive intelligence, but not reasoning intelligence. When the child begins to "notice things," to know its mother, to fear strangers, to be attracted by certain objects, we say it begins to show intelligence. Development in this direction goes on for a long time before it can form any proper judgment about things or take the step of reason.

If we were to subtract from the sum of the intelligence of an animal that which it owes to nature or inherited knowledge, the amount left, representing its own power of thought, would be very small. Darwin tells of a pike in an aquarium separated by plate-glass from fish which were its proper food, and that the pike, in trying to capture the fish, would often dash with such violence against the glass as to be completely stunned. This the pike did for three months before it learned caution. After the glass was removed, the pike would not attack those particular fishes, but would devour others that were introduced. It did not yet understand the situation, but merely associated the punishment it had received with a particular kind of fish.

During the mating season the males of some of our birds may often be seen dashing themselves against a window, and pecking and fluttering against the pane for hours at a time, day after day. They take their own images reflected in the glass to be rival birds, and are bent upon demolishing them. They never comprehend the mystery of the glass, because glass is not found in nature, and neither they nor their ancestors have had any experience with it.

Contrast these incidents with those which Darwin relates of the American monkeys. When the monkeys had cut themselves once with any sharp tool, they would not touch it again, or else would handle it with the greatest caution. They evinced the simpler forms of reason, of which monkeys are no doubt capable.

Animals are wise as Nature is wise; they partake, each in its own measure, of that universal intelligence, or mind-stuff, that is operative in all things--in the vegetable as well as in the animal world. Does the body, or the life that fills it, reason when it tries to get rid of, or to neutralize the effects of, a foreign substance, like a bullet, by encysting it? or when it thickens the skin on the hand or on any other part of the body, even forming special pads called callosities, as a result of the increased wear or friction? This may be called physiological intelligence.

But how blind this intelligence is at times, or how wanting in judgment, may be seen when it tries to develop a callosity upon the foot as a result of the friction of the shoe, and overdoes the matter and produces the corn. The corn is a physiological blunder. Or see an unexpected manifestation of this intelligence when we cut off the central and leading shoot of a spruce or of a pine tree, and straightway one of the lateral and horizontal branches rises up, takes the place of the lost leader, and carries the tree upward; or in the roots of a tree working their way through the ground much like molten metal, parting and uniting, taking the form of whatever object they touch, shaping themselves to the rock, flowing into its seams, the better to get a grip upon the earth and thus maintain an upright position.

In the animal world this foresight becomes psychic intelligence, developing in man the highest form of all, reasoned intelligence. When an animal solves a new problem or meets a new condition as effectually as the tree or the body does in the cases I have just cited, we are wont to ascribe to it powers of reason. Reason we may call it, but it is reason not its own.

This universal or cosmic intelligence makes up by far the greater part of what animals know. The domestic animals, such as the dog, that have long been under the tutelage of man, of course show more independent power of thought than the uneducated beasts of the fields and woods.

The plant is wise in all ways to reproduce and perpetuate itself; see the many ingenious devices for scattering seed. In the animal world this intelligence is most keen and active in the same direction. The wit of the animal comes out most clearly in looking out for its food and safety. We are often ready to ascribe reason to it in feats shown in these directions.

In man alone does this universal intelligence or mind-stuff reach out beyond these primary needs and become aware of itself. What the plant or the animal does without thought or rule, man takes thought about. He considers his ways, I noticed that the scallops in the shallow water on the beach had the power to anchor themselves to stones or to some other object, by putting out a little tough but elastic cable from near the hinge, and that they did so when the water was rough; but I could not look upon It as an act of conscious or individual intelligence on the part of the bivalve. It was as much an act of the general intelligence to which I refer as was its hinge or its form. But when the sailor anchors his ship, that is another matter. He thinks about it, he reasons from cause to effect, he sees the storm coming, he has a fund of experience, and his act is a special individual act.

The muskrat builds its house instinctively, and all muskrats build alike. Man builds his house from reason and forethought. Savages build as nearly alike as the animals, but civilized man shows an endless variety. The higher the intelligence, the greater the diversity.

The sitting bird that is so solicitous to keep its eggs warm, or to feed and defend its young, probably shows no more independent and individual intelligence than the plant that strives so hard to mature and scatter its seed. A plant will grow toward the light; a tree will try to get from under another tree that overshadows it; a willow will run its roots toward the water: but these acts are the results of external stimuli alone.

When I go to pass the winter in a warmer climate, the act is the result of calculation and of weighing pros and cons. I can go, of I can refrain from going. Not so with the migrating birds. Nature plans and thinks for them; it is not an individual act on the part of each; it is a race instinct: they must go; the life of the race demands it. Or when the old goose covers up her nest, or the rabbit covers her young with a blanket of hair and grass of her own weaving, I do not look upon these things as independent acts of intelligence: it is the cunning of nature; it is a race instinct.

Animals, on the whole, know what is necessary for them to know--what the conditions of life have taught their ancestors through countless generations. It is very important, for instance, that amphibians shall have some sense that shall guide them to the water; and they have such a sense. It is said that young turtles and crocodiles put down anywhere will turn instantly toward the nearest water. It is certain that the beasts of the field have such a sense much more fully developed than has man. It is of vital importance that birds should know how to fly, how to build their nests, how to find their proper food, and when and where to migrate, without instruction or example, otherwise the race might become extinct.

Richard Jefferies says that most birds'-nests need a structure around them like a cage to keep the young from falling out or from leaving the nest prematurely. Now, if such a structure were needed, either the race of birds would have failed, or the structure would have been added. Since neither has happened, we are safe in concluding it is not needed.

We are not warranted in attributing to any wild, untrained animal a degree of intelligence that its forbears could not have possessed. The animals for the most part act upon inherited knowledge, that is, knowledge that does not depend upon instruction or experience. For instance, the red squirrels near me seem to know that chestnut-burs will open if cut from the tree and allowed to lie upon the ground. At least, they act upon this theory. I do not suppose this fact or knowledge lies in the squirrel's mind as it would in that of a man--as a deduction from facts of experience or of observation. The squirrel cuts off the chestnuts because he is hungry for them, and because his ancestors for long generations have cut them off in the same way. That the air or sun will cause the burs to open is a bit of knowledge that I do not suppose he possesses in the sense in which we possess it: he is in a hurry for the nuts, and does not by any means always wait for the burs to open; he frequently chips them up and eats the pale nuts.

The same squirrel will bite into the limbs of a maple tree in spring and suck the sap. What does he know about maple trees and the spring flow of sap? Nothing as a mental concept, as a bit of concrete knowledge. He often finds the sap flowing from a crack or other wound in the limbs of a maple, and he sips it and likes it. Then he sinks his teeth into the limb, as his forbears undoubtedly did.

When I was a boy and saw, as I often did on my way to school, where a squirrel had stopped on his course through the woods and dug down through two or three feet of snow, bringing up a beech-nut or an acorn, I used to wonder how he knew the nut was there. I am now convinced that he smelled it.

Why should he not? It stands the squirrel in hand to smell nuts; they are his life. He knows a false nut from a good one without biting into it. Try the experiment upon your tame chipmunk or caged gray squirrel, and see if this is not so. The false or dead nut is lighter, and most persons think this fact guides the squirrel. But this, it seems to me, implies an association of ideas beyond the reach of instinct. A young squirrel will reject a worthless nut as promptly as an old one will. Again the sense of smell is the guide; the sound-meated nut has an odor which the other has not. All animals are keen and wise in relation to their food and to their natural enemies. A red squirrel will chip up green apples and pears for the seeds at the core: can he know, on general principles, that these fruits contain seeds? Does not some clue to them reach his senses?

I have known gray squirrels to go many hundred yards in winter across fields to a barn that contained grain in the sheaf. They could have had no other guide to the grain than the sense of smell. Watch a chipmunk or any squirrel near at hand: as a friend of mine observed, he seems to be smelling with his whole body; his abdomen fairly palpitates with the effort.

The coon knows when the corn is in the milk, gaining that knowledge, no doubt, through his nose. At times he seems to know enough, too, to cut off his foot when caught in a trap, especially if the foot becomes frozen; but if you tell me he will treat his wound by smearing it with pitch or anything else, or in any way except by licking it, I shall discredit you. The practice of the art of healing by the application of external or foreign substances is a conception entirely beyond the capacity of any of the lower animals. If such a practice had been necessary for the continuance of the species, it would probably have been used. The knowledge it implies could not be inherited; it must needs come by experience. When a fowl eats gravel or sand, is it probable that the fowl knows what the practice is for, or has any notion at all about the matter? It has a craving for the gravel, that is all. Nature is wise for it.

The ostrich is described by those who know it intimately as the most stupid and witless of birds, and yet before leaving its eggs exposed to the hot African sun, the parent bird knows enough to put a large pinch of sand on the top of each of them, in order, it is said, to shade and protect the germ, which always rises to the highest point of the egg. This act certainly cannot be the result of knowledge, as we use the term; the young ostrich does it as well as the old. It is the inherited wisdom of the race, or instinct.

A sitting bird or fowl turns its eggs at regular intervals, which has the effect of keeping the yolk from sticking to the shell. Is this act the result of knowledge or of experience? It is again the result of that untaught knowledge called instinct. Some kinds of eggs hatch in two weeks, some in three, others in four. The mother bird has no knowledge of this period. It is not important that she should have. If the eggs are addled or sterile, she will often continue to sit beyond the normal period. If the continuance of the species depended upon her knowing the exact time required to hatch her eggs, as it depends upon her having the incubating fever, of course she would know exactly, and would never sit beyond the required period.

But what shall we say of Mrs. Annie Martin's story, in her "Home Life on an Ostrich Farm," of the white-necked African crow that, in order to feast upon the eggs of the ostrich, carries a stone high in the air above them and breaks them by letting it fall? This looks like reason, a knowledge of the relation of cause and effect. Mrs. Martin says the crows break tortoise-shells in the same way, and have I not heard of our own crows and gulls carrying clams and crabs into the air and dropping them upon the rocks?

If Mrs. Martin's statements are literally true,--if she has not the failing, so common among women observers, of letting her feeling and her fancies color her observations,--then her story shows how the pressure of hunger will develop the wit of a crow.

But the story goes one step beyond my credence. It virtually makes the crow a tool-using animal, and Darwin knew of but two animals, the man-like ape and the elephant, that used anything like a tool or weapon to attain their ends. How could the crow gain the knowledge or the experience which this trick implies? What could induce it to make the first experiment of breaking an egg with a falling stone but an acquaintance with physical laws such as man alone possesses? The first step in this chain of causation it is easy to conceive of any animal taking; namely, the direct application of its own powers or weapons to the breaking of the shell. But the second step,--the making use of a foreign substance or object in the way described,--that is what staggers one.

Our own crow has great cunning, but it is only cunning. He is suspicious of everything that looks like design, that suggests a trap, even a harmless string stretched around a corn-field. As a natural philosopher he makes a poor show, and the egg or the shell that he cannot open with his own beak he leaves behind. Yet even his alleged method of dropping clams upon the rocks to break the shells does not seem incredible. He might easily drop a clam by accident, and then, finding the shell broken, repeat the experiment. He is still only taking the first step in the sequence of causations.