We have all looked down through the clear water of brook or pond and
watched the gracefully poised trout or pickerel; but have we ever tried to
imagine what the life of one of these aquatic beings is really like?
"Water Babies" perhaps gives us the best idea of existence below the
water, but if we spend one day each month for a year in trying to imagine
ourselves in the place of the fish, we will see that a fish-eye view of
life holds much of interest.
What a delightful sensation must it be to all but escape the eternal
downpull of gravity, to float and turn and rise and fall at will, and all
by the least twitch of tail or limb,--for fish have limbs, four of them,
as truly as has a dog or horse, only instead of fingers or toes there are
many delicate rays extending through the fin. These four limb-fins are
useful chiefly as balancers, while the tail-fin is what sends the fish
darting through the water, or turns it to right or left, with incredible
swiftness.
If we were able to examine some inhabitant of the planet Mars our first
interest would be to know with what senses they were endowed, and these
finny creatures living in their denser medium, which after a few seconds
would mean death to us, excite the same interest. They see, of course,
having eyes, but do they feel, hear, and smell!
Probably the sense of taste is least developed. When a trout leaps at and
catches a fly he does not stop to taste, otherwise the pheasant feather
concealing the cruel hook would be of little use. When an animal catches
its food in the water and swallows it whole, taste plays but a small part.
Thus the tongue of a pelican is a tiny flap all but lost to view in its
great bill.
Water is an excellent medium for carrying minute particles of matter and
so the sense of smell is well developed. A bit of meat dropped into the
sea will draw the fish from far and wide, and a slice of liver will
sometimes bring a score of sharks and throw them into the greatest
excitement.
Fishes are probably very near-sighted, but that they can distinguish
details is apparent in the choice which a trout exhibits in taking certain
coloured artificial flies. We may suppose from what we know of physics
that when we lean over and look down into a pool, the fishy eyes which
peer up at us discern only a dark, irregular mass. I have seen a pickerel
dodge as quickly at a sudden cloud-shadow as at the motion of a man
wielding a fish pole.
We can be less certain about the hearing of fishes. They have, however,
very respectable inner ears, built on much the same plan as in higher
animals. Indeed many fish, such as the grunts, make various sounds which
are plainly audible even to our ears high above the water, and we cannot
suppose that this is a useless accomplishment. But the ears of fishes and
the line of tiny tubes which extends along the side may be more effective
in recording the tremors of the water transmitted by moving objects than
actual sound.
Watch a lazy catfish winding its way along near the bottom, with its
barbels extended, and you will at once realise that fishes can feel, this
function being very useful to those kinds which search for their food in
the mud at the bottom.
* * * * *
Not a breath of air stirs the surface of the woodland pond, and the trees
about the margin are reflected unbroken in its surface. The lilies and
their pads lie motionless, and in and out through the shadowy depths,
around the long stems, float a school of half a dozen little sunfish. They
move slowly, turning from side to side all at once as if impelled by one
idea. Now and then one will dart aside and snap up a beetle or mosquito
larva, then swing back to its place among its fellows. Their beautiful
scales flash scarlet, blue, and gold, and their little hand-and-foot fins
are ever trembling and waving. They drift upward nearer the surface, the
wide round eyes turning and twisting in their sockets, ever watchful for
food and danger. Without warning a terrific splash scatters them, and when
the ripples and bubbles cease, five frightened sunfish cringe in terror
among the water plants of the bottom mud. Off to her nest goes the
kingfisher, bearing to her brood the struggling sixth.
Later in the day, when danger seemed far off, a double-pointed vise shot
toward the little group of "pumpkin seeds" and a great blue heron
swallowed one of their number. Another, venturing too far beyond the
protection of the lily stems and grass tangle of the shallows, fell victim
to a voracious pickerel. But the most terrible fate befell when one day a
black sinuous body came swiftly through the water. The fish had never seen
its like before and yet some instinct told them that here was death indeed
and they fled as fast as their fins could send them. The young otter had
marked the trio and after it he sped, turning, twisting, following every
movement with never a stop for breath until he had caught his prey.
But the life of a fish is not all tragedy, and the two remaining sunfish
may live in peace. In spawning time they clear a little space close to the
water of the inlet, pulling up the young weeds and pushing up the sandy
bottom until a hollow, bowl-like nest is prepared. Thoreau tells us that
here the fish "may be seen early in summer assiduously brooding, and
driving away minnows and larger fishes, even its own species, which would
disturb its ova, pursuing them a few feet, and circling round swiftly to
its nest again; the minnows, like young sharks, instantly entering the
empty nests, meanwhile, and swallowing the spawn, which is attached to the
weeds and to the bottom, on the sunny side. The spawn is exposed to so
many dangers that a very small proportion can ever become fishes, for
beside being the constant prey of birds and fishes, a great many nests are
made so near the shore, in shallow water, that they are left dry in a few
days, as the river goes down. These and the lampreys are the only fishes'
nests that I have observed, though the ova of some species may be seen
floating on the surface. The sunfish are so careful of their charge that
you may stand close by in the water and examine them at your leisure. I
have thus stood over them half an hour at a time, and stroked them
familiarly without frightening them, suffering them to nibble my fingers
harmlessly, and seen them erect their dorsal fins in anger when my hand
approached their ova, and have even taken them gently out of the water
with my hand; though this cannot be accomplished by a sudden movement,
however dexterous, for instant warning is conveyed to them through their
denser element, but only by letting the fingers gradually close about them
as they are poised over the palm, and with the utmost gentleness raising
them slowly to the surface. Though stationary, they kept up a constant
sculling or waving motion with their fins, which is exceedingly graceful,
and expressive of their humble happiness; for unlike ours, the element in
which they live is a stream which must be constantly resisted. From time
to time they nibble the weeds at the bottom or overhanging their nests, or
dart after a fly or worm. The dorsal fin, besides answering the purpose of
a keel, with the anal, serves to keep the fish upright, for in shallow
water, where this is not covered, they fall on their sides. As you stand
thus stooping over the sunfish in its nest, the edges of the dorsal and
caudal fins have a singular dusty golden reflection, and its eyes, which
stand out from the head, are transparent and colourless. Seen in its
native element, it is a very beautiful and compact fish, perfect in all
its parts, and looks like a brilliant coin fresh from the mint. It is a
perfect jewel of the river, the green, red, coppery, and golden
reflections of its mottled sides being the concentration of such rays as
struggle through the floating pads and flowers to the sandy bottom, and in
harmony with the sunlit brown and yellow pebbles."
When the cold days of winter come and the ice begins to close over the
pond, the sunfish become sluggish and keep near the bottom,
half-hibernating but not unwilling to snap at any bit of food which may
drift near them. Lying prone on the ice we may see them poising with
slowly undulating fins, waiting, in their strange wide-eyed sleep, for the
warmth which will bring food and active life again.
3rd. Fish. Master, I marvel how the fishes live in the sea.
1st. Fish. Why, as men do a-land: the great ones eat up the
little ones.
Shakespeare.