So, wandering hither and thither, the backboned family, and especially the milk-givers, took possession of plains and mountain ranges, of forests and valleys, of deserts and fertile regions. But still another question remains—How has it come to pass that large animals which once ranged all over Europe and Northern Asia,—mastodons, tusked tapirs, rhinoceroses, elephants, sabre-toothed tigers, cave-lions, and hippopotamuses in Europe,[199] gigantic sloths and llamas in North America, and even many huge forms in South America, have either been entirely destroyed or are represented now only by scattered groups here and there in southern lands? What put an end to the “reign of the milk-givers,” and why have they too diminished on the earth as the large fish, the large newts, and the large lizards did before them?

Footnote 199. Picture Heading, Chap. X.

To answer this question we must take up our history just before the scene at the head of our last chapter,[200] which the reader may have observed does not refer, as the others have done, to the animals in the chapter itself. Nevertheless it has its true place in the series, for it tells of a time when the great army of milk-givers had its difficulties and failures as well as all the other groups, only these came upon them not from other animals but from the influence of snow and ice.

For we know that gradually from the time of tropical Europe, when all the larger animals flourished in our country, a change was creeping very slowly and during long ages over the whole northern hemisphere. The climate grew colder and colder, the tropical plants and animals were driven back or died away, glaciers grew larger and snow deeper and more lasting, till large sheets of ice covered Norway and Sweden, the northern parts of Russia, Germany, England, Holland, and Belgium, and in America the whole of the country as far south as New York. Then was what geologists call the “Glacial Period;” and whether the whole country was buried in ice, or large separate glaciers and thick coverings of snow filled the land, in either case the animals, large and small, must have had a bad time of it.

True, there were probably warmer intervals in this intense cold, when the more southern animals came and went, for we find bones of the hippopotamus, hyæna, and others buried between glacial beds in the south of England. But there is no doubt that at this time numbers of land

Footnote 200. Chapter XI., Europe in the Age of Ice.

animals must have perished, for in England alone, out of fifty-three known species which lived in warmer times, only twelve survived the great cold, while others were driven southwards never to return, and the descendants of others came back as new forms, only distantly related to those which had once covered the land.

Moreover, when the cold passed away and the country began again to be covered with oak and pine forests where animals might feed and flourish, we find that a new enemy had made his appearance. Man—active, thinking, tool-making man—had begun to take possession of the caves and holes of the rocks, making weapons out of large flints bound into handles of wood, and lighting fires by rubbing wood together, so as to protect himself from wild beasts and inclement weather.

In America and in England alike, as well as in Northern Africa, Asia Minor, and India, we know that man was living at this time among animals, many of them of species which have since become extinct, and with his rude weapons of jagged flint was conquering for himself a place in the world.

He must have had a hard struggle, for we find these flint implements now lying among the bones of hyænas, sabre-toothed tigers, cave-lions, cave-bears, rhinoceroses, elephants, and hippopotamuses, showing that it was in a land full of wild beasts that he had to make good his ground.

“By the swamp in the forest

The oak-branches groan,

As the savage primeval,

With russet hair thrown

O’er his huge naked limbs, swings his hatchet of stone.

“And now, hark! as he drives with

A last mighty swing,

The stone blade of the axe through

The oak’s central ring,

From his blanched lips what screams of wild agony spring!

There’s a rush through the fern-fronds,

A yell of affright,

And the Savage and Sabre-tooth

Close in fierce fight,

As the red sunset smoulders and blackens to night.”[201]

Many and fierce these conflicts must have been, for the wild beasts were still strong and numerous, and man had not yet the skill and weapons which he has since acquired. But rough and savage though he may have been, he had powers which made him superior to all around him. For already he knew how to make and use weapons to defend himself, and how to cover himself at least with skins as protection from cold and damp. Moreover, he had a brain which could devise and invent, a memory which enabled him to accumulate experience, and a strong power of sympathy which made him a highly social being, combining with others in the struggle for life.

And so from that early time till now, man, the last and greatest winner in life’s race, has been taking possession of the earth. With more and more powerful weapons he has fought against the wild beasts in their native haunts; and by clearing away the large forests, cutting up the broad prairies and pastures, and cultivating the land, he has turned them out of their old feeding grounds, till now we must go to the centre of Africa, the wild parts of Asia, or

Footnote 201. From “A Legend of a Stone Axe,” a clever and suggestive poem in the New Quarterly, April 1879. The text is slightly altered.

the boundless forests of South America, to visit in their homes the large wild animals of the great army of milk-givers.

* * * * *

Since, therefore, these forms are growing rarer every century, and some of them, such as the Dodo, Epyornis, and Moa among birds, and the northern sea-cow or Rhytina among milk-givers, have already disappeared since the times of history, we must endeavour, before others are gone for ever, to study their structure and their habits. For we are fast learning that it is only by catching at these links in nature’s chain that we can hope to unravel the history of life upon the earth.

At one time naturalists never even thought that there was anything to unravel, for they looked upon the animal kingdom as upon a building put together brick by brick, each in its place from the beginning. To them, therefore, the fact that a fish’s fin, a bird’s wing, a horse’s leg, a man’s arm and hand, and the flipper of a whale, were all somewhat akin, had no other meaning than that they seemed to have been formed upon the same plan; and when it became certain that different kinds of animals had appeared from time to time upon the earth, the naturalists of fifty years ago could have no grander conception than that new creatures were separately made (they scarcely asked themselves how) and put into the world as they were wanted.

But a higher and better explanation was soon to be found, for there was growing up among us the greatest naturalist and thinker of our day, that patient lover and searcher after truth, Charles Darwin, whose genius and earnest labours opened our eyes gradually to a conception so deep, so true, and so grand, that side by side with it the idea of making an animal from time to time, as a sculptor makes a model of clay, seems too weak and paltry ever to have been attributed to an Almighty Power.

By means of the facts collected by our great countryman and the careful conclusions which he drew from them, we have learned to see that there has been a gradual unfolding of life upon the globe, just as a plant unfolds first the seed-leaves, then the stem, then the leaves, then the bud, the flower, and the fruit; so that though each part has its own beauties and its own appointed work, we cannot say that any stands alone, or could exist without the whole. Surely then Natural History acquires quite a new charm for us when we see that our task is to study among living forms, and among the remains of those that are gone, what has been the education and the development of all the different branches, so as to lead to the greatest amount of widespreading life upon the globe, each having its own duty to perform. With the great thought before us that every bone, every hair, every small peculiarity, every tint of colour, has its meaning, and has, or has had, its use in the life of each animal or those that have gone before it, a lifelong study even can never weary us in thus tracing out the working of Nature’s laws, which are but the expression to us of the mind of the great Creator.

When we once realise that whether in attacking or avoiding an enemy it is in most cases a great advantage to all animals to be hidden from view, and that each creature has arrived at this advantage by slow inheritance, so that their colours often exactly answer the purpose, how wonderful becomes the gray tint of the slug, the imitation of bark in the wings of the buff-tip moth, the green and brown hues of the eatable caterpillars, the white coat of the polar bear, and the changing colour of the arctic fox, the ermine, and the ptarmigan, as winter comes on! And when, on the other hand, we find badly-tasting creatures such as ladybirds and some butterflies, or stinging animals like bees and wasps, having bright colours, because it is an actual advantage to them to be known and avoided, we see that in studying colour alone we might spend a lifetime learning how the winners in life’s race are those best fitted for the circumstances under which they live, so that in ever-changing variety the most beautifully-adapted forms flourish and multiply.

Then if we turn to the skeleton and the less conspicuous framework of the body, the flippers of the whale, the manatee, or the seal, doing the work of a fish’s fin and yet having the bones of a hand and arm, reveal a whole history to us when we have once learned the secret that in the attempt to increase and multiply no device is left untried by any group of animals, and so every possible advantage is turned to account.

Next, the wonderful instincts taught by long experience give us a whole field of study. We see how frogs and reptiles, and even higher animals such as marmots, squirrels, shrews and bears, escape the cold and scarcity of food in winter by burying themselves in mud, or in holes of trees or caves of the earth till spring returns; and while we find alligators burying themselves in cold weather in America, we find crocodiles, on the contrary, taking their sleep in the hot dry weather in Egypt because then is their time of scarcity.

Then we learn that the birds avoid this difficulty of change of climate in quite another manner. They with their power of flight have learned to migrate, sometimes for short distances, sometimes for more than a thousand miles, so that they bring up their young ones in the cool north in summer, when caterpillars and soft young insects are at hand for their prey, and lead them in the winter to the sunny south where food and shelter in green trees are always to be found. So long indeed has this instinct of migration been at work, that often we are quite baffled in trying to understand why they take this or that particular route for their flight, because probably, when the first stragglers chose it, even the areas of land and water were not divided as now, so that we must study the whole history of the changing geography of the earth to understand the yearly route of the swallow or the stork.

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