This region may some day become a big cattle-raising 

 country if the diseases of nagana and rinderpest can 

 be controlled. Some tribes practice a primitive form 

 of agriculture. Occasional locust swarms devastate 

 both the native vegetation and the cultivated crops. 



The monsoon region of India supports a very 

 large population. The land is divided into tiny plots, 

 plowed by donkey, ox, or water buffalo, and culti- 

 vated by hand tools. Elephants do some of the 

 heavier work. Tea leaves are harvested from bushes, 

 rice is grown, and teak lumber obtained from the 

 forest. Cattle and goats supply milk. 



Natives in the tropical rain forest make their liv- 

 ing by hunting and fishing. They live in rude huts 

 made of branches and leaves. Their hunting is done 

 with bows and poisoned arrows, blow pipes, and pits 

 dug in the ground. In better developed equatorial 

 lands they grow manioc from which tapioca and flour 

 are obtained, yams, sugar cane, pineapples, bananas, 

 and cocoa. Cocoanuts are important food in some 

 places. Coffee is cultivated extensively in South 

 America. Sap from which rubber is made was orig- 

 inally collected from scattered naturally growing 

 trees in the forest, but rubber trees are now grown 

 extensively in plantations. The tropics undoubtedly 

 are a potentially rich productive area, but this pro- 

 ductivity will not be fully realized until the natives, 

 who are best adapted to live in the area, can be edu- 

 cated and acquire the skills to develop it (Hadlow 

 1953). 



SUMMARY 



Noteworthy of tropical climates is the 

 uniformity of temperature and length of daylight 

 throughout the year. Rainfall varies from a distinct 

 seasonal distribution in some regions to constant and 

 very heavy in others. Correlated with the rainfall 

 gradient is a vegetation continuum from desert, to 



savanna, to tropical deciduous forest, to tropical rain 

 and cloud forests. The biomes recognized are those 

 of desert, tropical savanna, and tropical forest. Aside 

 from deserts there are one or more tropical savanna 

 biociations in Africa and in Australia and the Indo- 

 Malayan, African, and American tropical forest bioci- 

 ations. The tropical forest flora and fauna are of 

 great age and continuity, and it may well be that all 

 other biomes can be traced back in origin to the trop- 

 ical biota of mesozoic and paleozoic times. 



The flora and fauna of the tropical forest is 

 marked by the richness of their species compositions. 

 Correlated with this is the harshness and severity of 

 interspecific competition and predation. On the other 

 hand, except for ants and termites, few species reach 

 high levels of population density. Large herds of un- 

 gulate mammals occur, however, in the tropical 

 savanna. 



With uniform climate throughout the year, cold- 

 blooded animals may have several generations per 

 year and species of birds, though not the same indi- 

 viduals, may breed during every month. There is no 

 hibernation or period of dormancy, nor is there mi- 

 gration, except in regions of pronounced wet and dry 

 seasons. 



Cold-blooded forms, especially reptiles and arthro- 

 pods, reach a large size in the tropics, but birds and 

 mammals are generally smaller than their relatives in 

 temperate regions. Although animals occur in great- 

 est numbers and variety on the forest floor, many 

 different groups have evolved members largely re- 

 stricted to the arboreal stratum. 



The tropics are the native home of the black races. 

 Originally they made their living by hunting and 

 fishing, grazing of domesticated animals, and a primi- 

 tive form of agriculture. The tropics are potentially 

 a rich productive area, but this productivity will not 

 be fully realized until disease can be controlled and 

 the natives better educated. 



350 Geographic distribution of communities 



