The geographical distribution of animals, with a study of the relations ...

chap, i.] INTRODUCTORY.Having thus defined our subject, let us glance at the opinionsthat have generally prevailed as to the nature and causes ofthe phenomena presented by the geographical distribution ofanimals.It was long thought, and is still a popular notion, that themanner in which the various kinds of animals are dispersedover the globe is almost wholly due to diversities of climate andof vegetation. There is indeed much to favour this belief. Thearctic regions are strongly characterised by their white bearsand foxes, their reindeer, ermine, and walruses, their whiteptarmigan, owls, and falcons ;the temperate zone has its foxesand wolves, its rabbits, sheep, beavers, and marmots, its sparrowsand its song birds ;while tropical regions alone produce apes andelephants, parrots and peacocks, and a thousand strange quadrupedsand brilliant birds which arefound nowhere in the coolerregions. So the camel, the gazelle and the ostrich live in thedesert ; the bison on the prairie ; the tapir, the deer, and thejaguar in forests. Mountains and marshes, plains and rockyprecipices, have each their animal inhabitants ;•be thought, in the absenceand it might wellof accurate inquiry, that these andother differences would sufficiently explain why most of theregions and countriesinto which the earth is popularly dividedshould have certain animals peculiar to them and should wantothers which are elsewhere abundant.A more detailed and accurate knowledge of the productions ofdifferent portions of the earth soon showed that this explanationwas quite insufficient ; for it was found that countries exceedinglysimilar in climate and all physicalvery distinct animal populations.features may yet haveThe equatorial parts of Africaand South America, for example, are very similar in climateand are both covered with luxuriant forests, yet their animal lifeis widely different; elephants, apes, leopards, guinea-fowlsand touracos in the one, are replaced by tapirs, prehensiletailedmonkeys, jaguars, curassows and toucans in the other.Again, parts of South Africa and Australia are wonderfullysimilar in their soil and climate;yet one has lions, antelopes,zebras and giraffes ; the other only kangaroos, wombats, phalan-