Evening star. [volume] (Washington, D.C.) 1854-1972, 1911-11-12
FISH'S SEARCH FOR FOOD.
Use of Senses of Sight and Smell.
Development of Hearing.

From the National Review.
The thinking part Of the brain. which In
man is so developed, is very small and in
significant in fishes. There is some reason
for thinking that the activities Of fishes
are nearly all what is called reflex. A
message is sent inward to the brain and
the muscles at once contract. Sensations
are changed into movement and actions
take place without thinking. Reflex &C
tons are therefore, Immediately suggest
ed and directed by the influence OF ex-
ternal things.
Fear and anger are the chief emotions
of fishes, and the search for food and for
a mate chiefly occupy their activities.
With so simple brain 1t cannot be sup
posed that the whole range of their senses
can be very extensive.
The eyes are probably the most i'm
portant sense organs Of trout and II
has been shown by very interesting ex-
perirnents that the majority OF fishes
seek their food chiefly. II not entirely. by
sight. But certain number, such as the
eel family. appear to hunt for IT and
recognize 1t by the sense Of smell alone.
while a few species are also aided by
barbels and special organs Of touch. -
Whether fish can perceive the difference
between colors is problem that raises
fishermen. There are some who boldly
assert that fish are quite color blind. To
this the BIOLOGIST may reply that there Is
nothing in the general structure or fishes
eyes or In the microscopic structure Of
the retina to prove that this must be so.
The difficulty Is that we know little
about the causes of color blindness In
human beings. In man color blindness Is
congenital and incurable. 1t is probably
due to unknown conditions of the retina
or the nerves or possibly both. Whether
the same conditions affect. fishes In the
same way one does not know.
On the other hand 1t seems extremely
improbable that fishes are quite incapable
of perceiving color, because male fish are
often more brightly c0lored In the breed
ing season. According to q theory, which
is still generally accepted. this is TO
make them attractive to their mates. VINO
perception of color. The evidence from
experiments on color sense In variety
of fishes is entirely negative; that Is 70
say. 1t goes to show that fish do not ais
criminate much between coIoIs. %
The sense of taste does not appear TO
be highly developed in any fishes; Most
of them bolt their food quickly and
without chewing. Closely allied with taste
is the sense Of smell 1t IS clear tnat
touch. vision or hearing. Whether this
sense should be called smell or taste IN
the case of an animal living and breath
ing in the water is difficult to decide.
Smell to a fish would perhaps be
equivalent to taste at a distance. We can
not argue from our own sensations.
Fishes have, however, olfactory organs.
and it is not unreasonable to suppose that
they should smell things az they. in
deed. appear to do.
There is plenty Of evidence that fishes
perceive violent shocks or conclusions.
such as those caused by firing guns or
on the bank. But there is no
evidence that their ears are capable OF
appreciating those delicate vibrations
which affect the senses Of ourselves or
other land animals and convey sensations
which we mean when We speak of hear
ing sounds. To that extent. therefore,
fish are deaf.