592 PHYSICAL GEOGRAPHY. 



In thus glancing at the zoology of the three great land divisions of the globe those of 

 America, of Europe, Asia, and Africa, and of New Holland we perceive instances of 

 different genera peculiar to each ; and even where the same genus occurs in these far sepa- 

 rated localities, the climates corresponding, the species are not identical. The animals of 

 the ape tribe ; of the canine and feline races, embracing wolves, foxes, hyaenas, lions, and 

 tigers ; of pachydermata, or the thick-skinned order, including elephants, tapirs, rhinoce- 

 roses, hogs ; of saurians and serpents ; of birds, aquatic, aerial, and terrene ; and of other 

 kinds, are all variously organised in the three great continents, as well as in different 

 climates of the same hemisphere. If we look to the zoology of small islands, situated at 

 no great distance from continents, like Great Britain, the Mediterranean isles, and Mada- 

 gascar, we find their animal races generally the same as those on the adjoining main- 

 lands ; and with reference to those that are isolated, and far from any continent, they 

 have commonly no land quadrupeds at all, except those that have been transported to 

 them by man, or have found their way thither by accidental means. Some of the 

 islets of the Keeling or Cocoo group, situated in the Indian Ocean, about six hundred miles 

 from the coast of Sumatra, are inhabited by rats, identical with the English species, which 

 were brought in a ship from the Mauritius, wrecked upon the shores. By the European 

 vessels, these troublesome parasites of the Old World, the rats and mice, have been con- 

 veyed to remote islets, bearing with as much impunity the heat of the equator as the cold 

 of the north. The great groups of the Pacific, upon their first discovery, presented no 

 warm-blooded animals, except a few tribes which had accidentally migrated or been con- 

 veyed by the natives, probably colonists from the Malayan archipelago. 



The conclusion to which we are led by the preceding facts with reference to animal 

 distribution, is clearly the 4 theory adopted in relation to the dispersion of plants, namely, 

 in the words of Prichard, that various tribes of organised beings were originally placed 

 by the Creator in certain regions, to which they are by their nature peculiarly adapted, 

 probably a single pair of each species, from which their offspring have dispersed them- 

 selves to as remote a distance from the original centre of their existence as their own 

 powers of locomotion, their capacity to endure change of climate, and the absence of 

 physical obstacles of migration, have enabled them to wander. In the case of birds and 

 insects, the agency of the winds has been a potent cause of dispersion, and some well- 

 known circumstances illustrate the mode by which animals of considerable size may be 

 conveyed to shores distant from their original location, and become the occupants of 

 islands to which, apparently, the ocean forbids the advance of animal life from without, 

 unless transported thither by man. The common brown fox is found in Greenland and in 

 Iceland, and has been borne from the former to the latter by the drifting ice, a mode of 

 conveyance which has been observed in operation, for Olafsen mentions, that on one occa- 

 sion he saw no fewer than four on one piece, sailing away on some such voyage of 

 discovery. The animals perish if the ice makes no land, as is the case with immense 

 fields which reach the heart of the Atlantic, and melt in the warm water of the gulf- 

 stream ; but should it gain a shore, the living cargo may be disembarked, introducing a 

 new species to the district, or multiplying one previously brought there in the same way. 

 It is not uncommon for the northern voyager to hear the wolves fearfully howling as 

 they die by famine, having taken to the ice in the pursuit of seals, and been set afloat, 

 hunger overtaking them in the open sea. Several animals, as the rat, dog, and bear, can 

 accomplish considerable distances by their own powers of swimming ; and the recent 

 occurrences of the Moray floods show, contrary to a popular sentiment, that the common 

 swine is adequate to the same performance. Three members of the same litter compassed 

 the distance of five miles ; and one, after being carried down to the mouth of the Spey, 

 swam four miles, and landed safe. Mr. Lyell remarks, that " in an adult and wild state, 



