NATURAL REGIONS OF THE GLOBE 11 
rence of many bulbous plants, speaks to a climate where 
dry and wet seasons alternate, and so on. The depen- . 
dence of the more active animal upon its surroundings is 
less intimate than that of the passive plant, but even 
here the characters of the animals of a region tell us 
something of the physical features of that region. That 
we find in Brazil, for example, animals so thoroughly 
adapted to the arboreal life as sloths, marmosets, 
monkeys, and so forth, suggests at once that dense 
forest occurs in the region. That Africa has an 
enormous number of antelopes—enormous both as 
regards species and individuals—suggests the existence 
in that continent of open plains, and so with other 
regions. 
The botanists recognize three great plant formations, 
which roughly divide the surface of the land among 
them. These are woodland, grassland, and desert. 
Such a simple division would help us little in the case 
of animals, but as all animals depend ultimately for 
their food upon plants, a modification of this classi- 
fication may serve as a framework in the study of 
animal distribution. There is, for example, a consider- 
able difference in the life conditions of animals which 
live in regions where the winter cold periodically checks 
plant growth, as compared with those where no such 
temperature check occurs. This gives us a first dis- 
tinction between the animals of cold or temperate 
regions and those of tropical regions. In both of these 
forest, grassland, and desert occur, but it is possible to 
pick out certain well-defined types in order to study 
their faunas separately. Thus, among the various forms 
of temperate forest, the Taiga or coniferous forest of 
Asia and North America has a well-defined assemblage 
of animals showing some interesting adaptations. 
