Intelligence in Plants and Animals / Being a New Edition of the Author's Privately Issued "Soul and Immortality."

by Thomas G. Gentry

All is not play, however, even among the Dace. The warm days of June usher in the sterner duties, the nesting-time. Male and female join in the preparation, and a locality, perhaps in shallow water in some running brook, is selected. Roots, snags and leaves are carried away, both fishes sometimes found tugging away at a single piece, taking it down-stream, and working faithfully and vigorously until, in a few hours, a clearing over two feet in diameter is the result.

There the first eggs are laid. The male, who has retired, soon appears from up-stream, bearing in his mouth a pebble, which is placed in the centre of the clearing. Now they both swim away, but soon returning, each bearing a pebble, that is also dropped upon the eggs. Slowly the work proceeds, until a layer of clean pebbles apparently covers the eggs. A second layer of eggs is now deposited by the female, and these are covered by pebbles as the others had been, the industrious little workers scouring the neighborhood for them, seemingly piling up eggs and stones alternately until the heap attains a height of eight inches or more. These heaps vary in shape, some being pyramidal, and others dome-shaped.

Such patience as these finny housekeepers manifest is not appreciated by man. The gleaners of the golden fields, in whose waters our little friends are found, have not discovered their secret, and think the curious piles the washes of the brook itself. But their purpose is the protection of their eggs. In swift-running streams, which these fish are so wont to affect, the eggs would be washed away, and, driven against rocks and snags, would be destroyed, or, even escaping destruction, would, by the undulating movement to which they would become subjected, be rendered impossible of incubation. Besides, were they not thus protected, even though there was no danger of being washed away, they would become easy prey to the attacks of carnivorous fishes.

Unlike as the Lamprey-eels are in structure to the Dace, yet in their habits of erecting a nest they are very similar. Upon our Eastern sea-board they are a common species, inhabiting both salt and fresh water. In the early spring they follow the shad up the rivers, occasionally preceding them, and search about for suitable localities in which to deposit their spawn. They clean away the stones as the Dace were seen to do, bending their long bodies in coils, which they use in pushing aside the accumulation on the bottom. To the unlearned the appearance of two Eels, each three feet in length, twisting and seemingly coiling about each other, would be indicative of war. But having cleaned for themselves a smooth spot, the Lampreys proceed to place stones. Irregularly-shaped stones of small size are easily and quickly transported in their mouths, but when stones that weigh several pounds are to be brought, the tactics they adopt are worthy of an engineer. As the spots chosen for the rearing of their submarine castles are ordinarily subjected to a swift current, the largest stones, which it would be thought impossible for them to move, are looked for up stream. A suitable one found, and a favorable position presented, the sucking mouth is fastened to it, and by a convulsive effort, the tail of the fish being raised aloft, the heavy stone is lifted from its place, the current pushing against the fish and stone, bearing them along several feet before they sink. Another effort of the fish, and the rock is again raised and carried down stream, until finally, by repeated liftings and struggles, the ingenious, persevering nest-builder is swept down to the nest, where the load is deposited. This laborious work is carried on until the pile has attained a height of two or three feet, and a diameter of four. No special form seems to be necessary. The nest is generally oval, compact and well devised to contain the eggs, which are carefully deposited within, thus affording protection in its numerous interstices for the young when they hatch. When about six inches long, the young Petromyzon marinus, which is a strange little fellow, is devoid of teeth, and blind, and possesses so many characteristics distinct from the parent, that for a long time he was considered a separate species, and even assigned a place in a different genus. Enormous nests are sometimes built. John M. Batchelder, Esq., describes one, which he saw in the Saco River, Maine, that was about fifteen feet long, and from one to three feet in height, its position and triangular shape in vertical section being well adapted for securing a change of water, and a hiding-place for the young. The operation of building was very methodical, a hundred and more Eels being at work upon the structure. Water-worn stones, chips of granites and fragments of bricks, sometimes weighing as much as two pounds and transported by a single individual, were utilized in the building.

BLACK-NOSED DACE.
Constructing Their Nest of Pebbles.

More remarkable, however, than any previously described, are the nests of the Fresh-water Chub, Semotilus bullaris, which is known in some localities as the Stone Toter. This fish attains a length of about fifteen inches. The finest nests are on the shores of Westminster Island, but they are common on nearly every island that has a sandy, gravelly shore among the many that make up the Thousand Islands. The nest is a pile of stones, sometimes measuring ten feet across at the base, four feet in height, and containing a good-sized cart-load of stones, weighing in all perhaps a ton. Stones from small pebbles to some four inches in length were used, and as some of the nests are placed at considerable distances from the gravel-beds, and each stone represented a journey, the amount of labor performed, when it is considered that tens of thousands of stones must have been used in the building, certainly was incredible. Each stone is brought in the mouth of the Chub and dropped over the piles, one or more fishes working at the same heap. Some plan is evidently followed in the work, the first deposit of stones being small, and dropped so as to form a circle or semi-circle. The largest heaps are undoubtedly the work of successive years, the nests being annually added to during the last of May or June, when the Chubs are seen lying in the heaps, at which time the eggs are probably deposited. All the labor of piling up is to protect them from predatory fishes, a necessary and wise provision, as cat-fish, rock-bass, perch and others prey upon the eggs.

In gravelly beds the Trout excavates a simple nest, a mere depression in the sand, that is not at all incomparable to the nest of some species of gulls. A furrow in the gravelly bottom of a river, often ten feet in length, the depression being made as fast as it is required, is the nest of the Salmon. In Canadian rivers these nests can be easily distinguished by the lighter marking in the bottom.

Few persons of the many who delight to drift along our sea-shores are unfamiliar with the Toad-fish. So closely does he in shape and color resemble a moss-covered stone that his enemies are deceived. Intrenched among the weeds and gravel, which the mother-fish carelessly throws aside, after the fashion of some of the gulls, the young are reared, their yolk-sacs enabling them to cling to the rocks of the nest soon after birth. There, under the watchful eye of the parent, they remain until old enough to swim away.

But the most vigilant of all nest-builders is the Four-spined Stickleback—Apeltes quadracus. In some neighboring stream, that sooner or later finds its way to the ocean, he may be found. There are different species of these fish, but their architectural ideas are pretty much the same. They vary mainly in the locations they select for nesting. Some place the nests upon the bottom, concealed among the sea-weed found there, while others hang theirs from some projecting ledge, or swing it in the tide from the sunken bough of some overhanging tree. As is unusual, the work of nidification is solely performed by the male Stickleback, the female taking no part in the labor. The spawning season having arrived, he, assuming a bright nuptial lustre, shows remarkable activity in selecting a site for an edifice, and transporting the building material thither. Fragments of all kinds of plants, gathered often at a distance, are brought home in his mouth. These are arranged as a sort of a carpet, but as there is danger of the light materials being carried away by the current, they are weighted down by sand to keep them in their places. Having entwined them with his mouth to his complete satisfaction, he then glides gently over them on his belly, and glues them with the mucus that exudes from his pores. More solid materials, sometimes bits of wood, sometimes bits of straw, which he seizes with his mouth, are adjusted to the sides of the floor to constitute the walls. He is now very particular. If the piece cannot be properly adjusted to his building, and he does not lose patience in his efforts to fit it in, he carries it to some distance from the nest and leaves it. After the side walls are erected, a roof of the same materials with the floor is laid over the chamber. Firmness is given to the whole structure by passing over it with his body, the light and useless particles being fanned away by the action of his fins and the vibratory movements of his tail. In carrying on his building operations care is taken to preserve a circular opening into the chamber, his head and a great part of his body being thrust therein, thus widening and consolidating it, and rendering it a fit receptacle for the female. When choosing material, the fish has been seen testing its specific gravity by letting it sink once or twice in the water, and if the descent was not rapid enough finally abandoning it.