THE BAT’S SENSES OF SMELL AND HEARING
“Bats are nocturnal,” Uncle Paul continued the next day; “that is, they
leave their lurking-places only at nightfall, to hunt in the evening
twilight. As a rule, animals addicted to nocturnal hunting have very
large eyes that take in as much light as possible, and thus these
animals can see with very little light. Night-birds, such as owls of
all kinds, will furnish us a remarkable example a little later. By a
singular exception, however, despite their nocturnal habits bats have
very small eyes. How, then, are they able to direct themselves in their
swift flight, so abrupt in its changes of direction? How, above all,
are they aware of the presence of their tiny game—moths and gnats?
“They are guided especially by their senses of smell and hearing, which
are extraordinarily acute. What do you say to the bat’s ears in this
picture? What animal of its size can show anything like them? How they
flare, like enormous hearing-trumpets, to receive the slightest sound!
The bat that bears them has the expressive name of long-eared bat.”
“Long-eared bat,” repeated Jules; “that’s the kind of name I like; it
describes the animal and shows what there is about it that is out of
the ordinary.”
“Such prodigious ears are certainly made to hear sounds inaudible to us
by reason of their excessive faintness. They enable their possessor to
hear at a distance the beating of a moth’s wings and the fluttering of
a gnat dancing in the air.
“Other bats which have smaller ears have as a substitute a sense of
smell unequaled for its acuteness. The high state of perfection of this
sense is the result of the abnormal development of the nose, which
covers a good part of the face and gives the animal a very strange
appearance. For example, here is the head of a bat called the horseshoe
bat. This broad, distended formation of curious shape that occupies
almost the whole space between the eyes and the mouth is the nose. It
ends above in a large triangular, leaflike expanse; laterally it
spreads out in folded laminæ, all together taking the shape of a
horseshoe, whence the name of the creature. What odor, however faint,
could escape such a nose? The dog, so famous for its keenness of scent,
chases the hare without seeing it, guided solely by the odor left
behind by the animal, heated in the chase; but how much keener the
scent of the horseshoe bat must be when it chases in the same manner a
moth that leaves no odor for any nose but its pursuer’s! I sometimes
wonder whether such a nose, so abnormally developed, may not be able to
detect certain qualities that are and always will be unknown to us for
want of the means to perceive them. The horseshoe bat’s grotesque nose
makes you laugh, my little friends; it makes me think. I think of the
thousand secrets that nature hides from our senses and that would be as
easy for us to learn as they would be valuable if we possessed the
scent of a poor bat. Perhaps (who can tell?) the horseshoe bat foresees
with its nose the coming storm several days in advance; it may scent
the future hurricane, smell the rain-clouds coming from the other end
of the earth, know by detecting their odor what winds are about to
blow, foretell in similar manner what the weather is going to be; and,
guided by perceptions of which we can form no idea, it may make its
plans for hunting insects that are sometimes abundant and sometimes
scarce according to the state of the atmosphere.”
“If the horseshoe bat’s nose can do all that,” said Jules, “we must
agree that it is a first-rate sort of nose.”
“I make no positive assertions,” his uncle rejoined. “I merely have my
suspicions. The only thing that seems to me beyond doubt is that such
an organ as the bat’s nose serves its owner as a source of sensations
unknown to man.”
“You say so many wonderful things about it, Uncle,” Emile interposed,
“that I shall end by thinking the horseshoe bat’s nose much more
curious than ugly. There’s another thing, too, I’ve just noticed. Why
does the creature have such fat cheeks? See what a puffed-up face it
has in the picture.”
“With the bat,” Uncle Paul explained, “the chase is a short one,
lasting only one or two hours—in fact, the short interval between
sunset and dark. The remainder of the twenty-four hours is passed in
rest, in the quiet of some cavern or grotto. Does the animal, then,
have but one meal in all this time? And what if there are evenings when
hunting is out of the question, the sky being overcast, the wind too
strong, or rain falling, so that the insects keep under cover? The bat
would then be subjected to long fasts if it were impossible for it to
lay in supplies beforehand. But these supplies must be collected
hastily, on the wing, with no interruption to the hunt which lasts so
short a time. Hence it is that pouches are indispensable, deep pouches
in which the hunter can put his game as fast as he catches it. The
cheeks exactly fill this office: they can be enlarged at the creature’s
will—distended so as to form roomy pockets in which the insects killed
with a snap of the teeth can be stowed away. These reserve pockets are
called cheek-pouches. Gluttonous monkeys have them. That is where the
she-ape, fond of sweets, puts the lump of sugar given her and lets it
slowly melt so as to prolong the enjoyment of it. Well, when the bat is
out hunting it first satisfies its hunger, and then—especially when its
nose, the famous nose that we have just been talking about, predicts
unfavorable weather for the following days—it redoubles its exertions
and stows away moth after moth in the depths of its elastic pouches. It
returns to its quarters with cheeks all distended. Now without fear of
famine it can remain idle for several days if necessary. Hanging
motionless by a hind claw, it feeds on its store of provisions,
nibbling one at a time, as hunger prompts, the insects softened to
taste in the reservoir of its cheeks.
“But it is high time we finished with the bats; their history would be
too long if I were to tell you all about them. I will only ask Jules
what he thinks now of the animal he at first called hideous.”
“Frankly, Uncle,” answered the boy, “these creatures interest me now
more than they disgust me. Their singular wings, formed at the cost of
what might have been hands, their prodigious nose and immense ears
which make up for their poor eyesight, their cheeks swollen so as to
make pouches for their supply of food—all these have interested me very
much.”
“The cheek-pouches,” said Emile, “where the bat puts its game to soak,
and the nose that scents the coming storm, seemed to me the most
curious things about the animal.”
“And I,” said Louis, “shall never forget how many enemies bats deliver
us from.”
“Now you understand,” Uncle Paul rejoined, “or at least I hope you are
beginning to understand, that bats, being so useful to us in destroying
a multitude of ravaging insects, and noteworthy for their singular
structure, should not inspire us with an unjustifiable repugnance and
still less with a stupid rage to exterminate them. Let us leave in
peace these poor creatures that so valiantly earn their living by
protecting our crops. Do not let us harm them under the foolish pretext
that they are ugly, for their supposed ugliness is in reality an
admirable adaptation of bodily structure to the creature’s mode of
life.”