Daily Mail - Daily Mail Weekend Magazine
SIR DAVID’S PLEA
Creatures that have survived for millennia now depend on us, says the series narrator
Why don’t polar bears eat penguins? The riddle is probably as old as any other that you will find in a Christmas cracker. And the answer is not difficult to work out: penguins and polar bears live at opposite ends of the world and never meet.
But why is that so? To answer that question, you have to consider the Earth’s geological history. Three hundred million years ago, the only land on this planet’s otherwise oceancovered surface was a single supercontinent. It was there that terrestrial life began. Eventually, however, this immense landmass began to break up. One fragment started to drift south. As it approached the pole, it became so cold that none of its animal passengers were able to survive. This was the continent we now call Antarctica and no land animals – except human beings – have ever managed to reach it since.
Questions about why different animals live where they do are likely to occur to anyone who watches a natural history series surveying the entire globe, as Seven Worlds, One Planet does. But not all are so easily answered. Why, for example, is it deer that nibble grass in North America, whereas the medium-sized mammals that live in Africa in a similar fashion and with a similar diet are antelope? Or why are there apes in the tropical forests of Africa and Asia but none at all in the jungles of South America?
Seven Worlds, One Planet helps to answer such questions. It also explains why communities of animals and plants on the seven continents of our planet are still so different from one another that they can justifiably be described as separate worlds.
Each has its own particular animal treasures. Some are rare and little known. Take, for example, the olm that lives only in the caves of eastern Europe. It is a kind of salamander, as long and as slim as a small snake, and has two pairs of diminutive legs and a moist, scale-less skin. Because it lives in permanent darkness, it has lost its eyes and the pigment in its skin and so has become a ghostly white. Now its life is so uneventful and requiring so little energy that it only needs to eat once in a decade.
Or consider the blue-faced goldencoated monkey that lives in northern China in places that are snow-covered for at least five months of the year. It is so cold there that the monkeys have developed thick furry coats and reduced the danger of their noses being frostbitten by evolving ones that are so severely snubbed that they can hardly be described as noses at all. Both these strange creaare tures rare and scarcely known because they live in restricted and littlevisited habitats. There are, however, other rarities whose numbers are also small but for very different and more alarming reasons. They were once abundant but we have displaced them from the territories that were once theirs. Sometimes we have done so for the most trivial of reasons. During the 19th century, European settlers both in Australia and North America introduced blackbirds and thrushes from Europe because they considered that their songs were more melodious than those of the local birds. They imported foxes because the hunters among them had nothing they thought suitable for the chase. And some brought their pet cats because they enjoyed having them sitting purring by the fireside. Some of these introductions failed and died out after a few generations. But others flourished and became plagues that had catastrophic effects on the indigenous animal populations.
Others of our introductions have been accidental rather than deliberate, as on the many occasions when we have allowed rats, hitchhiking on our ships, to escape ashore in territory where they never existed before. Again and again these hardy, omnivorous and prolific intruders
have then caused havoc among the local animals which had no defence against them.
But the greatest changes we have caused are those we have made deliberately in order to provide for our everincreasing numbers. We have felled forests, drained swamps and covered fertile meadows with concrete in order to build our homes and factories, airports and motorways. So, over the past 200 years, wild animals that were once relatively abundant on every continent except Antarctica have been decimated and now survive in dangerously small numbers. Such are the Iberian lynx, European wolf, Arctic musk ox and many others.
Seven Worlds, One Planet describes and illustrates rarities of both kinds, together with some of the most dramatic natural wonders that still remain on Earth. Let us hope that our increasing understanding of the way nature functions will at last persuade people everywhere to care for the animals that evolved on this planet’s continents and allow them the space they need to live in the particular world that once was theirs. n