NATURAL REGIONS OF THE GLOBE 13 
Europe and North America, and of the animals of the 
Mediterranean or scrub forest, found round the Mediter- 
ranean Sea, in California, and elsewhere. We shall find, 
however, that such regions have for the most part 
a transitional fauna, made up of units from the sur- 
rounding regions, and that further they have been 
much altered by man’s interference. It is true that the 
effects of this interference are often interesting, for 
while some animals die out as civilization spreads, 
others, like the rats, the common sparrow, the cock- 
roaches, some parasites, and so on, adjust themselves 
to the altered conditions, and prosper under civiliza- 
tion as they never did in former days. But a considera- 
tion of these points would take us too far from our 
immediate subject. We shall therefore confine our- 
selves to a consideration of the nine natural regions 
already given, and fill up whatever gaps this method 
may leave by a final consideration of the zoogeogra- 
phical regions into which zoologists have divided the 
globe. But as the greater part of this book is thus 
devoted to the geographical aspect of animal distribu- 
tion, a word or two may be added in further explanation 
of the difference between the two points of view, the 
zoological and the geographical. 
To the zoologist it is a fact of great interest 
that the sloths, ant-eaters, and armadillos should 
occur in South America, and nowhere else. But the 
geographer is more interested in the fact that the sloth 
is a purely arboreal animal, fitted only for life in the 
dense forest, while the armadillo, for example, shows 
adaptations to quite other habitats. The difference 
between the sloth of the Amazon forest and the squirrel 
of the Siberian taiga, again, means something very 
different to zoologist and geographer, for the latter 
