Tadpole

“ From almost every country pond, or ditch, or swamp, a chorus of voices rises up in the springtime of the year, calling to us to come and learn how Life has taught her children to pass from the water to the air; for it is then that the frogs lay their eggs, and every tadpole which grows up into a frog carries us through the wonderful history of an animal beginning life as a fish with water-breathing gills, and ending it as a four-legged animal with air-breathing lungs. ”

“ Then went there from thy star—for I know now 'twas thine—a momentary flash across the head of the tadpole, and again another and another, rapidly, pertinaciously. And from thy star there passed repeated flashes across the head of the tadpole, till his brilliance was as 'twere severed from him, and he, like drossy silver, a dead shape in the conspicuous heavens. And he became yellow as the rolling eyes of sick wretches in pain, and shrank in his place like pale parchment at the touch of flame ”

“ Not one instance have we of tadpoles that have fallen to this earth. It seems reasonable that a whirlwind could scoop up a pond, frogs and all, and cast down the frogs somewhere else: but, then, more reasonable that a whirlwind could scoop up a pond, tadpoles and all—because tadpoles are more numerous in their season than are the frogs in theirs: but the tadpole-season is earlier in the spring, or in a time that is more tempestuous. ”

“ The transformation of the tadpole from an aquatic animal into an aerial one is abundantly curious, when first it is hatched from the spawn by the warmth of the season, it resembles a fish; it afterwards puts forth legs, and resembles a lizard; and finally losing its tail, and acquiring lungs instead of gills, becomes an aerial quadruped. ”

“ The tadpole, on the contrary, goes on swimming about freely, and keeping the use of its eyes, till at last a pair of hind legs and then a pair of fore legs begin to bud out from its side, and its tail fades away, and its gills disappear, and air-breathing lungs take their place, and it boldly hops on shore a fully evolved tailless amphibian. ”

“ The food of the tadpole is the minute plant life on the stones, the surface of the mud, or on the outside of the larger plants.
One must not attempt to raise too many tadpoles in the artificial pond in the laboratory or school-room or there will not be enough food, and all will be half starved, or some will get the food and the rest will starve to death. While there may be thousands of tadpoles in the natural pond, it will be readily seen that, compared with the amount of water present, there are really rather few. ”

“ The tadpole, as a unique larval type among vertebrates, bears the hallmarks of an abrupt adaptive shift, such as might have occurred within the limits of a single family, and it seems difficult to imagine the enclosed branchial chamber, the tooth-rows, and lips of a familiar tadpole as having evolved without some kind of suctorial function along the way. ”

“ It is absurd to call the larva of a newt or of a Caecilian a tadpole, nor is the free-swimming embryo of a frog as it leaves the egg a tadpole. A tadpole is the larva of a tailless Batrachian after the loss of the external gills and before the egress of the fore limbs (except in the aberrant Xenopus) and the resorption of the tail. What characterizes a tadpole is the conjoined globular head and body, so formed that it is practically impossible to discern the limit between the two, sharply set off from the more or less elongate compressed tail which is the organ of propulsion. ”

“ We lived in a snug little hole under the bank of the river, and in front of our dwelling was a large stone on which we could sit and watch the baby tadpoles grow. Although they loved best to lie in the mud at the bottom of the river, we knew that exercise is necessary to the proper development of a tadpole ”

“ Tadpoles feed on insects and also on each other. They are admirable preparers of small skeletons. Try the tadpole at this trade; drop into his pond a dead mouse, or bird, or frog, or squirrel. Soon you will find a clean, white skeleton, nice enough to put in any museum.
The food of the adult frog is chiefly insects. Less hungry than when in the tadpole state,—for the tadpole like the [Pg 227] child must not only eat to live but to grow—the frog is not often tempted to vary his diet. ”

“ But look in this vase: here are several tadpoles with the most apologetic of tails—mere stumps, in fact. I cut them off nine days ago."
"Will they grow again?"
"Perfectly; for, although the frog dispenses with a tail almost as soon as he reaches the frog form, the tadpole needs his tail to swim with; and when by any accident he loses it, Nature kindly supplies him with another." ”

“ The older they grow the oftener do they come to the surface. This is even more marked in the large tadpole of the bullfrog. What is the meaning of this? Probably most of the pupils can guess correctly; but it took scientific men a long time to find out just why this was done. The real reason is that the tadpole is getting ready to breathe the free air above the water when it turns into a toad and lives on the land. At first the little tadpoles breathe the air dissolved in the water, just as a fish does. This makes it plain why an artificial pond should have a broad surface exposed to the air. ”

“ To the teacher.—From the dark area of the egg the tadpole develops, the dark colour absorbs the sunlight, and this causes growth. The jelly holds the eggs up so that the sun can reach them and it also keeps them from being swept away by the water. The tadpole is very small, and external gills are needed to keep it in very close contact with the water. The tail does not drop off, the substance in it is absorbed into the body of the growing toad to serve as nutriment. ”

“ The tadpole has very small eyes, a very small mouth, and tiny gill openings like a fish. Indeed, so far as its life at this stage is concerned, to all intents and purposes it is a fish. It cannot live out of the water, it breathes by gills, it swims by its tail, but it has no fins. It wiggles about the jar or tank in a very lively way, and ought to have water weeds or stones to hide under, and pebbles or gravel in the bottom of the receptacle. ”

“ Then the Eels talked among themselves about them. "I shall be glad," said one old Father Eel, "when these youngsters hide their breathing-gills and go to the top of the water."
"So shall I," exclaimed a Mother Eel. "They keep their tails wiggling so that it hurts my eyes to look at them. Why can't they lie still and be good?"
Now the Tadpoles looked at each other with their shining black eyes. "What are our breathing-gills?" they asked. "They must be these little things on the sides of our heads."
"They are!" cried the First Tadpole. "The Biggest Frog said so. ”

“ The creature which comes from this egg is no more like a frog, than a caterpillar is like a butterfly. It has a big head and no limbs, and what of it is not head seems to be tail. In fact, in this stage the creature is more like a fish than a frog, and has branched gills. The gills are nearly covered by a fold of skin. Have you seen it? It is a tadpole. This tadpole can live only in water, and swims and feeds from the first instant of its free life. ”

“ Undeceive yourselves: they go to the water only to lay their eggs or to escape from some danger or to bathe in hot weather, but they could not remain under water any length of time without dying. They have to come up at intervals to breathe, which they do by getting at least the nostrils out. Here we have a difference between the tadpole and the full-grown batrachian, between the larva, so to speak, and the creature at its maturity: the tadpole lives in water and perishes in the air, whereas the frog that comes from it lives in the air and perishes in water. ”

“ Nothing would be easier than for a piece of spawn or a tiny tadpole to be washed into some hole in a mine or cave, where there was sufficient water for its developement, and where the trickling drops brought down minute objects of food, enough to keep up its simple existence. A toad brought up under such peculiar circumstances might pass almost its entire life in a state of torpidity, and yet might grow and thrive in its own sleepy vegetative fashion. ”

“ Now this complete development which the tadpole goes through in one summer is, after all, but a rapid repetition, as it were, of that slow and gradual development which must have taken place in past ages, when water-breathing animals first became adapted to air-breathing. Any one, therefore, who will take the spawn of a frog from a pond, and watch it through all its stages, may rehearse for himself that marvellous chapter in the history of the growth and development of higher life. ”

“ All these changes are familiar and natural, but until science places them and similar facts in their proper relations their significance is lost to us. The tadpole is essentially a fish in its general structure and mode of life, even though its heritage is such that it can develop into a higher animal. When it does become a frog it proves beyond a doubt that there is no impassable barrier between fishes and amphibia. ”

“ I don't mean when they are so small that it seems a kindness to call them tadpoles at all, but when they are quite a good size, with great fat heads and shiny little eyes and squiggly little tails. And how many of you can tell me the number of different kinds of tadpoles which one can find in England in the springtime? Most of you, I am sure, know a tadpole when you see one (sometimes he is called "pot-ladle,"or "polly-wog," {30} or "horse-nail,") and some of you may know that a fat frog-tadpole is brown with little specks of gold, while a fat toad-tadpole is black all over ”

“ LEVIATHAN, n. An enormous aquatic animal mentioned by Job. Some suppose it to have been the whale, but that distinguished ichthyologer, Dr. Jordan, of Stanford University, maintains with considerable heat that it was a species of gigantic Tadpole (Thaddeus Polandensis) or Polliwig—Maria pseudo-hirsuta. ”

“ The ordinary tadpole, if well fed, astonishes and delights his young keepers in a few days by putting forth a pair of tiny hind legs, which generally trail behind him when he swims, though he often kicks with them, perhaps for exercise. ”

“ The tadpole and the ascidian larva divide between them the honour of preserving for us in all its native simplicity the primitive aspect of the vertebrate type. Beasts, birds, reptiles, and fishes have all descended from an animal whose shape closely resembled that of these wriggling little black creatures which dart up and down like imps through the clear water, and raise a cloud of mud above their heads each time that they bury themselves comfortably in the soft mud of the bottom. ”

“ Each of them begins life as essentially a fish—that is to say, as a tadpole breathing oxygen dissolved in water, by means of gills, and possessed of no limbs for terrestrial locomotion; he ends it as essentially a full-grown land-reptile, breathing atmospheric air by means of lungs, having discarded his now needless fin-fringed tail, and possessed of jumping legs of great muscular power. ”

“ The tadpole which hatches out of this egg is very much like that of a toad or a frog; but the front legs are the first to appear, instead of the hind legs, while the tail, of course, does not pass back into the substance of the body.
Newts swim with their tails, and very pretty and graceful they look as they move through the water. When they cease to be tadpoles, of course, they breathe air, just as toads and frogs do, and have to come up to the surface every two or three minutes to obtain it. And as long as they live in the pond they feed upon grubs and worms and tiny water-insects. ”

“ It is considered fair and decent that each batch of tadpoles should live in their prison (a milk bottle) only one week. The following Sunday they go back to the pond, and a new generation take their places. There is some subtle kinship, we think, between children and tadpoles. No childhood is complete until it has watched their sloomy and impassive faces munching against the glass, and seen the gradual egress (as the encyclopædia pedantically puts it) of their tender limbs, the growing froggishness of their demeanour. ”

“ During the early stages of its existence it is in turn, a fin-tailed tadpole with no legs, a short-tailed tadpole with a pair of front legs, a shorter-tailed tadpole with four legs, and finally a fully-developed, land-going frog with a voice like a small bull, and no tail whatever. ”

“ PEEPS INTO NATURE'S NURSERIES. I.—THE LIFE-HISTORY OF THE COMMON FROG
(Concluded from page 12.)
We come now to the final stages in the life of the tadpole babies. These are indicated by the appearance of a pair of tiny buds on each side of the base of the tail; day by day they grow longer and longer, and finally assume the form of the hind-leg of the adult. ”

“ The progress of a tadpole from a fish to a quadruped by his gradually putting forth his limbs, and at length leaving the water, and breathing the dry air, is a subject of great curiosity, as it resembles so much the incipient state of all other quadrupeds, and men, who are aquatic animals in the uterus, and become aerial ones at their birth. ”

“ When the air became purer, the gills were changed into the imperfect lungs of the amphibious tribes, such as the huge saurians and the frogs. Deprive these latter animals, in their lower stage, of [Pg 13] all access to the light, and they will not advance to their higher stage. Put a tadpole into a perforated box, and sink it to the bottom of a river, and the animal will never be perfected into a frog; he will grow to an enormous size, but he will continue a tadpole. ”