The aegis & intelligencer. [volume] (Bel Air, Md.) 1864-1923, 1902-03-28
SENSITIVE TO SOUND
ACUTE POWERS OF HEARING WITH
WHICH FISH ARE ENDOWED.

|
| Some Interesting Experiments That
Were Made to Determine Just What
Manner of Noises or Motions Would
Startle Trout.
There are three phases of sense in
fish particularly interesting to the an
Gler-their exquisite powers of hearing,
of seeing and their subtle, abnormal
sensitiyeness to atmospheric influence.
With all our experience and study 1t is
doubtful if we have arrived at any
thing like Il full estimate of the acute
sensitiveness with which fish are en-
dowed. l devote this article to hear
ing. By hearing | must obviously be
understood to mean their power of ap-
preciating the vibration caused by
sound, the conductor being either solid,
aerial or liquid.
In man sound detonates the eardrum,
and in that way when we are under
water we discover little Ineligible
meaning from sounds. But the same
vibrations are undoubtedly received by
the eXquisltely sensitive hearing intel
ligence of fish, If I may use the
term, in a different and far more i'm
pressive way. By intelligence l mean
an instructive recognition by their
bodies OF some disturbance, Just as
man recognizes passing breath Of air.
1t takes the form Of feeling.
came to the conclusion that !
would make few experiments. Here
are one or two facts: A friend entered
into 1t with me, and we bethought our
selves Of certain well known trout in
our preserve which were always
there" Then we placed matched hur-
dies day or two beforehand so that
the fish might get accustomed to them
in such way that we could approach |
close to their haunts without being
seen and watch the unsuspecting trout |
through a small hole cut in the straw. |
When one was not at home, the other |
generally was My friend undertook |
the noise making, the observation.
From the sound Of a gunshot 500 |
yards away, which made our trout dis |
tinctly start, to the breaking of twig |
three yards from the fish. which did |
the same, we tried all kinds of sounds, |
shrill and dull and at varying dis |
tances, and the sum of our experiments |
convinced US of this: That our sensi- |
lively organized friends felt the dis
placements of molecules through ether, |
which we call sound, and the further |
vibrating disturbance through what we |
call water, which / verify believe con-
ducts sensation to the fish as readily |
as glass permits the penetration Of
light to this paper, in proportion to the
distances and the character of the
sound. but that they did hear. or feel
rather. and with incredible quickness,
too. was concluslvely demonstrated.
What they heard and were not alarm
ed Mt cannot tell, but when they were
alarmed 1t was evident enough by the
same kind of start they give when their
chief enemy suddenly peeps over the
bank. In only two cases could dis
cover actual fright, the fright that
sends them dOwn-a gunshot behind
the hurdle and n heavy stamp of the
foot near by. 1t Is noteworthy that the
shrill sounds seemed to startle them
tie at ten yards sent one out into the
stream as If looking about for some
source Of danger. whereas a shout at
the same distance caused no detected
movement. Their way of shifting a
little farther from the bank when they
have an inliling of danger is very
pretty side movement. well known no
doubt. 1t seems for the purpose Of
watching the bank at a better angle.
The common manner of showing
their alarm was by a sudden CULVER,
sometimes followed by sinking down
an inch or two, as much as to say,
What's up" l very much doubt If !
ever crept up to my peephole without
being detected, and yet l was careful,
for, If you notice, trout once on the
qui vive gives no sign Of alarm at a
pared he Is immovable till he suddenly
darts Off. You may throw your great
coat at him. and he either braves 1t stol-
idly or bolts cleans away. Five minutes
perfect stiffness and they settle back to
and then they were again
easily startled. l fancy the laws Of re-
fraction had something to do with 1t
and that even from the sky they some
times perceived my movements. l had
often suspected this before.
Another conclusions: ! believe they
heard much they appeared not to. A
sudden smack Of the hands together,
and there was a decided culver, but a
bird rattle. begun very softly and grad
ually brought up to its very loudest,
and no notice seemed to be taken. But
like ourselves, however loud
the noise, the gradient robs 1t Of its
Btartle. However fanciful 1t may
sound, Of this l am thoroughly con-
water is such an immedi-
ate transmitter of vibration to fish that
they recognize sound from the air near
~ as quickly as man. 1t is no argu-
ment to say we do not when in 1t. We
have no need. Fish have. And be-
rause they have they are providentially
endowed with supersensitivenesst to that
particular nervous influence among
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