Professor Garner has studied simian speech so carefully that he is able to converse with Monkeys to a limited extent. He says they have words for "food" and "drink," have a spoken salutation, and can distinguish numbers up to about three, and have some notion of music. "In brief, they appear to have at least the raw material out of which are made the most exalted attributes of man."
Aristotle noticed that voices vary with conditions when he gravely announced that the Calf affords the only instance in nature where the voice of the young is deeper and graver than that of its parent. Wild animals frequently change their voices on domestication. Domestic Dogs and even tame Jackals have learned to bark, which is a noise not proper to any species of the genus, with the possible exception of the Canis latrans of North America. Columbus discovered that Dogs left by him on an island where there was no game nor any other occasion for barking lost their voices completely before he visited them on a subsequent voyage. Some breeds of domestic Pigeons coo in a new and quite peculiar manner not manifested in their wild state.
The same species of birds living in different localities sometimes have different vocal habits. An excellent observer says an Irish covey of Partridges spring without uttering a call, while, on the opposite coast, the Scotch covey accompany their springing with intense shrieks. Bechstein says that from many years of experience he is certain that in the Nightingale a tendency to sing in the middle of the night or in the day runs in families and is strictly inherited.
As the Parrot acquires human language by association with unfeathered bipeds, so do many voices modify themselves as circumstances alter, and the particular sound which one day may accompany and express fright or anger may be laid aside for another more suitable to new conditions, much as a man uses different sounds in asking for butter at a French restaurant and in a German inn. And while it is probably not true that speech was given for the purposes of communicating with others, it has occurred in nature that speech has become the principal means of transmitting ideas.
An old Goose had her nest in the kitchen of a farmer. She had been endeavoring for a fortnight to hatch some eggs, but was taken ill rather suddenly and found she could not finish the task. With evident agony she repaired to an outhouse where was a Goose of but one year's growth. In some way she told the young sister that her valuable mission was about to be interrupted ere its fulfillment and implored her to become her successor. So complete was the communication between them that the young one entered the kitchen and took her place, with evident maternal pride, remaining there till the eggs were hatched and afterwards caring assiduously for the welfare of the Goslings. The old Goose expired contentedly before incubation was complete.
A gentleman who visited London occasionally was usually accompanied by a small Dog. Nearing the city, he put up at an inn and left the Terrier there to await his return. Once, as he came back from London, the Dog was not there. He had had a fight with a large Housedog and been so badly wounded that it was thought he would not recover. But after lying quietly for a couple of days he disappeared. About a week later he returned with a larger animal, sought his adversary, and by union of efforts gave him a terrible punishment. It was found that his coadjutor was a neighbor, and that the wounded animal must have traveled long to visit his friend, had been able to tell him of his sorrows, awaken his sympathies, and keep him enlisted in his cause all the while they were on their way to seek their enemy, and was no doubt able to congratulate his partner many times during the homeward journey on the success of their valorous enterprise.
Professor Morgan says: "I find that the sounds emitted by young Chicks are decidedly instinctive—that is to say, they are inherited modes of giving expression to certain emotional states. And some of them are fairly differentiated. At least six may be distinguished: First, the gentle, piping sound expressive of contentment—for example, when one takes the little bird in one's hand. A further low note, a sort of double sound, seems to be associated with extreme pleasure, as when one strokes the Chick's back. Very characteristic and distinct is the danger note. This is heard on the second or third day. If a large Humble-bee, or a black Beetle, or a big lump of sugar, or in fact anything largish and strange, be thrown to them this danger note is at once heard. Then there is the piping sound, expressive apparently of wanting something. It generally ceases when one goes near them and throws some grain, or even only stands near them. My Chicks were accustomed to my presence in the room, and generally were restless, and continuously made this sound when I left them. Then there is the sharp squeak when one seizes a Chick against its inclination. Lastly there is the shrill cry of distress, when, for example, one of them is separated from the rest. I have very little doubt that all of these sounds have a suggestive value of emotional import for the other Chicks. Certainly the danger-note at once places others on the alert, and the pleasure-note will cause others to come to the spot where the little bird is when the note is sounded."
A good story is told by H. B. Medlicott to show what ideas wild pigs can express in sounds. "In the early dawn of a gray morning I was geologizing along the base of the Muhair hills in South Behar, when all of a sudden there was a stampede of many Pigs from the fringe of a jungle, with porcine shrieks of sauve-qui-peut significance. After a short run in the open they took to the jungle again, and in a few minutes there was another uproar, but different in sound and in action; there was a rush, presumably of the fighting members, to the spot where the row began, and after some seconds a large Leopard sprang from the midst of the scuffle. In a few bounds he was in the open, and stood looking back, licking his chaps. The Pigs did not break cover, but continued on their way. They were returning to their lair after a night's feeding in the plain, several families having combined for mutual protection; while the beasts of prey were evidently waiting for the occasion. I was alone, and though armed, I did not care to beat up the ground to see if in either case a kill had been effected. The numerous herd covered a considerable space, and the scrub was thick. The prompt concerted action must in each case have been started by a special cry. I imagine that the first assailant was a Tiger, and the case was at once known to be hopeless, the cry prompting instant flight, while in the second case the cry was for defense. It can scarcely be doubted that in the first case each adult Pig had a vision of a Tiger, and the second of a Leopard or some minor foe."
The structure of throats that talk and sing varies greatly, and scientists have yet much to learn about the adaptations of forms to purposes. Agassiz gives the following clear description of the throats of birds: "The proper larynx is very simple, destitute of vocal chords, and incapable of producing sounds; but at the lower end of the windpipe there is a second or inferior larynx, which is very complicated in structure. It is a kind of bony drum, having within it two glottises, formed at the top of the two branches of the windpipe, each provided with two vocal chords. The different pieces of this apparatus are moved by peculiar muscles, the number of which varies in different families. In birds which have a very monotonous cry, such as the Gulls, the Herons, the Cuckoos, and the Mergansers, there is but one or two pairs; Parrots have three; and birds of song have five." But there are still further items regarding special uses that make the question hard to solve.
Some throats that have apparently the same structure as far as the scalpel and microscope can distinguish have marvelously different powers of delivery. MacGillivray has pointed out that the Rook and the Hooded Crow seem to have just as complex an apparatus for their sepulchral utterances as the Nightingale and the Blackbird. But where loudness of sound is required without regard to range and quality there are some notable conformations, as in the Whooping Crane and the Howling Monkey. This Monkey has large cavities communicating with the glottis, and the air reverberates as it passes the larynx so the most deafening noises are produced.