How do we differ from all other living creatures? Not in having hands; the monkeys have four hands, and if hands were the test of humanity, would be twice as human as we. Not in lacking coats of fur or features; pigs and elephants have skins as bare as ours. Nor is it that we walk on two legs; the birds do that, and the kangaroos. The difference is not even in the fact that we have no tails; for some of the apes also are as tailless as we are. Besides, when you come to think of it, most animals do not have tails—insects do not, nor clams and oysters, nor sea-anemones and star-fish, nor corals and sponges, nor frogs and toads, nor jelly-fish; even the birds, unless you count the feathers as part, do not have tails that one could really wag.

After all, too, we human beings do have tails; or at least a string of tail bones, an inch or more long, tucked away inside our skins. This coccyx bone, as it is called, is the place where it hurts so fearsomely when you sit down too hard on a pebble or a bicycle bar, and it catches you in one little spot just at the end of the back bone. When that happens, you may remember that the difference between you and the animals is not altogether in tail bones. Once in a while, too, men do have veritable tails, as large as a finger, and round and curly like a pig’s.

The one essential difference between ourselves and all other creatures on the earth is neither in hands nor skins nor legs nor tails, but in talking. We can talk and the animals cannot.

But you say right off, parrots can talk. Oh, no, they can’t! Parrots can speak, in the sense that they can say words; but that is a quite different thing from talking. Dumb people, tho they cannot speak, have no difficulty in learning to talk with their fingers. The parrot can be taught to repeat words, whole sentences, even pieces of poetry—but no parrot ever learns to talk about the things that he is interested in. No parrot, for example, ever tries to tell about the forest where he was born, nor his voyage to this country, nor the animals he met in the store before he was bought. He, says “Polly wants a cracker”; but he doesn’t say, “I want to get out of this cage and fly about”; and no two parrots ever yet tried to converse with one another.

How different it is with children. They try to talk long before they can. They pick up words for themselves. They talk with one another; and when they don’t know the word for something they want to say, they make one up. Don’t you remember various words that you and your playmates invented, that other people do not know the meaning of? In short, we human beings have a talking instinct; just as birds have a nest-building instinct, and squirrels an instinct for hiding nuts in the ground.

So if we should take a lot of robin’s eggs, hatch them out in an incubator, feed the little birds by hand and never let them see a grown up bird or a nest, there is no doubt that when the proper time came they would sing, build nests, and take care of their young, much as if they had been brought up by their parents in the usual manner. In the same way, if we should take a lot of tiny babies and bring them up where they never heard a word of speech, there is little doubt that when it became time for them to talk, they would invent for themselves a language to talk with. Indeed, some people think that the reason why there are so many different languages in the world, hundreds and hundreds as there are, is because at various times children have been lost, or all the old people of a tribe have died, and the children having no one to teach them their parents’ tongue, have had to make up a new language for themselves.

But no animal could possibly do this. Whether because they lack this strange talking instinct, or because they simply haven’t anything in particular that they want to say, no group of animals has ever invented a language, nor has any single animal ever learned to talk our human speech. A parrot can utter words; a dog can understand them. But somehow no creature except ourselves ever puts the two together, and talks.

I don’t think we ever half realize what an advantage this being able to talk is to us, nor how utterly helpless we should be without it. Suppose for example you are lost in a strange city. You stop the first passerby, and you say “I want to find such and such a street.” “So many blocks up or down,” he answers, “so many to the right or left”; and with one or two more simple questions from time to time, there you are right on your doorstep.

But suppose your dog gets lost. He can not stop the next dog or man he sees and say, “I belong to Mr. So-and-so on Such-and-such Street; tell me how to get home.” All he can do is to look up into some one’s face and whine; and that may mean equally well, “lam lost,” or “I am hungry,” or “I want a drink,” or “The little boy that owns me has gone into that house and I wish he’d hurry up and come out,” or “I don’t like the place where I am living because there is a horrid cat there that scratches me on the nose, and I wish I could go home and live with you instead,” or “I know you have been in a meat market, because I can smell the nice smell of the fresh meat, and I wish I were going to have some for my dinner in place of dog biscuit which I don’t like.”

All these ideas, and forty others like them, the dog would have to express in precisely the same way, and leave to his hearer to guess which one he might happen to mean this particular time. In fact, about all the ideas that a dog can express are, “I want something that I haven’t got,” “I am afraid I’m going to get something I don’t want,” and “If somebody doesn’t look out, there’s going to be a very dickens of a row here in about a minute.” What he may think beyond these simple matters he has pretty much to keep to himself.

And did you ever think how extremely difficult it would be to learn anything, lacking words to learn it with? You can tell the capitals of the United States, or the chief rivers of Asia, or the kings of England, because somebody who knew has told somebody else, and he somebody else, until the information has at length filtered down to you. Whatever you do not know and want to know, you can find out from somebody who does know, either by asking directly or by looking in a book where somebody has written it down. But a dog can find out things only by seeing them for himself, and when he does find them out, he has no way of telling any other dog anything about them.

No wonder that cow I was telling you about a short while ago was not in the least surprised when her calf ripped apart and the hay fell out. Why should she not think that all calves are stuffed with hay, and are expected sooner or later to rip apart and provide hay for their mammas’ supper? She has no way of finding out what calves are made of inside. If you wanted to know, you would ask. She couldn’t.

I suppose a child going to school and asking questions at home and getting them answered, as every child should, learns at least a hundred times as fast as any animal can possibly learn. I suppose too that a dog or cat, living in one place and doing about the same things every day, learns in a year or two all that there is to be known about his particular world, and so finds out nothing more all the rest of his life. You learn for lessons something new every day, you see new people, and visit new places, you have new things to eat, and new clothes. But the animals always have the same clothes, and the same things to eat. Most of them do not travel; if they do sometimes make new friends, the new friends cannot tell them anything. Think, then, how ignorant must be the rabbit shut up in one pen, the cow confined to one pasture, the parrot always in the same cage. They do the same things day after day; in a week they have learned all there is to be known.

Of course, an animal cannot tell time nor count; for telling time and counting require words. He cannot give names to anything, nor remember anything by name, nor think about anything in words. Indeed, it is pretty difficult, without words, to do any thinking at all. We can learn, think, remember, plan, contrive, teach, ask questions, answer them, because we have words to work with. The animals have no words. Therefore, the wisest of them is like a child of four.