Throughout the depths of the sea, silence, as well as absolute darkness,
prevails. The sun penetrates only a short distance below the surface, at
most a few hundred feet, and all disturbance from storms ceases far above
that depth, Where the pressure is a ton or more to the square inch, it is
very evident that no sound vibration can exist. Near the surface it is
otherwise. The majority of fishes have no lungs and of course no vocal
chords, but certain species, such as the drumfish, are able to distend
special sacs with gas or air, or in other ways to produce sounds. One
variety succeeds in producing a number of sounds by gritting the teeth,
and when the male fish is attempting to charm the female by dashing round
her, spreading his fins to display his brilliant colours, this gritting of
the teeth holds a prominent place in the performance, although whether the
fair finny one makes her choice because she prefers a high-toned grit
instead of a lower one can only be imagined! But vibrations, whether of
sound or of water pressure, are easily carried near the surface, and
fishes are provided with organs to receive and record them. One class of
such organs has little in common with ears, as we speak of them; they are
merely points on the head and body which are susceptible to the watery
vibrations. These points are minute cavities, surrounded with tiny _cilia_
or hairs, which connect with the ends of the nerves.
The ears of the frogs and all higher animals are, like the tongue-bone and
the lower jaw, derived originally from portions of gills, which the
aquatic ancestors of living animals used to draw the oxygen from the
water. This is one of the most wonderful and interesting changes which the
study of evolution has unfolded to our knowledge.
The disproportionate voices are produced by means of an extra amount of
skin on the throat, which is distensible and acts as a drum to increase
the volume of sound. In certain bullfrogs which grow to be as large as the
head of a man, the bellowing power is deafening and is audible for miles.
In Chile a small species of frog, measuring only about an inch in length,
has two internal vocal sacs which are put to a unique use. Where these
frogs live, water is very scarce and the polliwogs have no chance to live
and develop in pools, as is ordinarily the case. So when the eggs are
laid, they are immediately taken by the male frog and placed in these
capacious sacs, which serve as nurseries for them all through their
hatching and growing period of life. Although there is no water in these
chambers, yet their gills grow out and are reabsorbed, just as is the case
in ordinary tadpoles. When their legs are fully developed, they clamber up
to their father's broad mouth and get their first glimpse of the great
world from his lower lip. When fifteen partly developed polliwogs are
found in the pouches of one little frog, he looks as if he had gorged
himself to bursting with tadpoles. To such curious uses may vocal organs
be put.
Turtles are voiceless, except at the period of laying eggs, when they
acquire a voice, which even in the largest is very tiny and piping, like
some very small insect rather than a two-hundred-pound tortoise. Some of
the lizards utter shrill, insect-like squeaks.
A species of gecko, a small, brilliantly coloured lizard, has the back of
its tail armed with plates. These it has a habit of rubbing together, and
by this means it produces a shrill, chirruping sound, which actually
attracts crickets and grasshoppers toward the noise, so that they fall
easy prey to this reptilian trapper. So in colour, sound, motion, and many
other ways, animals act and react upon each other, a useful and necessary
habit being perverted by an enemy, so that the death of the creature
results. Yet it would never be claimed that the lizard thought out this
mimicking. It probably found that certain actions resulted in the approach
of good dinners, and in its offspring this action might be partly
instinctive, and each generation would perpetuate it. If it had been an
intentional act, other nearly related species of lizards would imitate it,
as soon as they perceived the success which attended it.
That many animals have a kind of language is nowadays admitted to be a
truism, but this is more evident among mammals and birds, and, reviewing
the classes of the former, we find a more or less defined ascending
complexity and increased number of varying sounds as we pass from the
lower forms--kangaroos and moles--to the higher herb-and-flesh-eaters, and
particularly monkeys.
Squeaks and grunts constitute the vocabulary, if we dignify it by that
name, of the mammals. The sloths, those curious animals whose entire life
is spent clinging to the underside of branches, on whose leaves they feed,
may be said almost to be voiceless, so seldom do they give utterance to
the nameless wail which constitutes their only utterance. Even when being
torn to pieces by an enemy, they offer no resistance and emit no sound,
but fold their claws around their body and submit to the inevitable as
silently and as stoically as did ever an ancient Spartan.
Great fear of death will often cause an animal to utter sounds which are
different from those produced under any other conditions. When an elephant
is angry or excited, his trumpeting is terribly loud and shrill; but when
a mother elephant is "talking" to her child, while the same sonorous,
metallic quality is present, yet it is wonderfully softened and modulated.
A horse is a good example of what the fear of death will do. The ordinary
neigh of a horse is very familiar, but in battle when mortally wounded, or
having lost its master and being terribly frightened, a horse will scream,
and those who have heard it, say it is more awful than the cries of pain
of a human being.
Deer and elk often astonish one by the peculiar sounds which they produce.
An elk can bellow loudly, especially when fighting; but when members of a
herd call to each other, or when surprised by some unusual appearance,
they whistle--a sudden, sharp whistle, like the tin mouthpieces with
revolving discs, which were at one time so much in evidence.
The growl of a bear differs greatly under varying circumstances. There is
the playful growl, uttered when two individuals are wrestling, and the
terrible "sound"--no word expresses it--to which a bear, cornered and
driven to the last extremity, gives utterance--fear, hate, dread, and
awful passion mingled and expressed in sound. One can realise the fearful
terror which this inspires only when one has, as I have, stood up to a mad
bear, repelling charge after charge, with only an iron pike between one's
self and those powerful fangs and claws. The long-drawn moan of a polar
bear on a frosty night is another phase; this, too, is expressive, but
only of those wonderful Arctic scenes where night and day are as one to
this great seal-hunter.
The dog has made man his god,--giving up his life for his master would be
but part of his way of showing his love if he had it in his power to do
more. So, too, the dog has attempted to adapt his speech to his master's,
and the result is a bark. No wild coyotes or wolves bark, but when bands
of dogs descended from domesticated animals run wild, their howls are
modulated and a certain unmistakable barking quality imparted. The
drawn-out howl of a great gray wolf is an impressive sound and one never
to be forgotten. Only the fox seems to possess the ability to bark in its
native tongue. The sounds which the cats, great and small, reproduce are
most varied. Nothing can be much more intimidating than the roar of a
lion, or more demoniacal than the arguments which our house-pets carry on
at night on garden fences.
What use the sounds peculiar to sea-lions subserve in their life on the
great ocean, or their haunts along the shore, can only be imagined, but
surely such laudable perseverance, day after day, to out-utter each other,
must be for some good reason!
Volumes have been written concerning the voices of the two remaining
groups of animals--monkeys and birds. In the great family of the
four-handed folk, more varieties of sound are produced than would be
thought possible. Some of the large baboons are awful in their
vocalisations. Terrible agony or remorse is all that their moans suggest
to us, no matter what frame of mind on the part of the baboon induces
them. Of all vertebrates the tiny marmosets reproduce most exactly the
chirps of crickets and similar insects, and to watch one of these little
human faces, see its mouth open, and instead of, as seems natural, words
issuing forth, to hear these shrill squeaks is most surprising. Young
orang-utans, in their "talk," as well as in their actions, are
counterparts of human infants. The scream of frantic rage when a banana is
offered and jerked away, the wheedling tone when the animal wishes to be
comforted by the keeper on account of pain or bruise, and the sound of
perfect contentment and happiness when petted by the keeper whom it learns
to love,--all are almost indistinguishable from like utterances of a human
child.
But how pitiless is the inevitable change of the next few years! Slowly
the bones of the cranium thicken, partly filling up the brain cavity, and
slowly but surely the ape loses all affection for those who take care of
it. More and more morose and sullen it becomes until it reaches a stage of
unchangeable ferocity and must be doomed to close confinement, never again
to be handled or caressed.