96 THE FAUNA OP 



forest there is, as abeady indicated, no seasonal cheek 

 to vegetation, and therefore no marked variation in 

 the amount of vegetable food available. But there is 

 much evidence to show that the total amount is less 

 than might be expected. The tropical forests of New 

 Guinea yield almost no food for man, so that recent 

 expeditions have had to import every particle con- 

 sumed, and have at times run almost the same risks 

 of starvation as explorers in the tundra, even when 

 armed with modem weapons. Elsewhere there are few 

 human groups indeed who manage to subsist solely on 

 the products of the tropical forest, and those who do, 

 e. g. the Congo pygmies and the Philippine negritos, 

 seem to be few in number, and yet to suffer from chronic 

 starvation. They do not reach a high state of civiliza- 

 tion. The fact that aU the more intelligent of the 

 forest animals soon learn to rob man's plantations, or 

 to prey upon his flocks and herds, suggests that the 

 wild mammals are no better off than forest-dwelling 

 man. The reasons why the conditions should be 

 relatively unfavourable in the tropical forests are 

 perhaps a little obscure, but we note among them that 

 the physical conditions most favourable to plant life 

 are not those best suited to the mammalia at least. 

 Further, the enormous number of plant species in the 

 tropical forest diminishes the chance that a particular 

 useful species will occur in numbers. The fact that 

 trees of commercial value only occur in isolated speci- 

 mens is a great barrier to the exploitation of the tropical 

 forest by man, and it has doubtless also its effect on 

 the wild animals. If there is one Cembra pine loaded 

 with ripe seeds in the taiga, there will almost certainly 

 be many in the vicinity ; if the squirrels find one 

 hickory tree in the American woods whose nuts are 



