A NATURALIST IN BRAZIL 



The same wealth of forms is found among the mammals ; of the 

 Rodents, for example, some are aquatic animals, some resemble 

 small Ungulates, and others correspond to our hares and other 

 species. 



This extensive division of the various families has led many 

 scientists to believe that South America consisted formerly of a 

 number of islands, each of which evolved its own individual fauna. 

 To this one must object that the age-long isolation of the continent, 

 with the fact that it is divided into many different types of landscape, 

 would suffice to explain such variety. Even to-day von Ihering dis- 

 tinguishes six different regions in Brazil, of which each has its 

 special avian fauna, while other birds are common to several, and 

 some to all regions. These regions are : Amazonas ; the country to 

 the south of Para ; the Sertao of the North-east ; the interior of the 

 southern States; the northern coastal zone, originally forest-clad; 

 and the southern coastal zone, characterized rather by high grassy 

 plains. The bird life of Amazonas in particular is wholly peculiar to 

 the country. 



But there is a second factor which favours the division of species 

 in South America. This is the circumstance that the greater part 

 of the continent lies within the tropics. A few figures will show the 

 great difference which exists in respect of the wealth of species 

 between tropical and temperate countries. Of the 2,286 species of 

 fresh- water fish in the list of fishers drawn up by the London Natural 

 History Museum, 1,552, or more than two-thirds, are tropical species. 

 The river system of the Brahmaputra-Ganges has 170 species; that 

 of the Mackenzie in Canada has only 23 ; and while the Amazon 

 boasts of 748 species, the whole of Europe numbers only 126. And 

 so with the birds, of which Brazil has 1,600 species, and the Argentine 

 887. The insect life of the tropics is especially rich in species ; in 

 India, for example, there are nearly 30,000, while in Greenland 

 only 437 are known. Of snakes, 727 species are found in the Philip- 

 pines, but in Japan, whose area is half as great again, only 193. 



The explorer Bates relates that within an hour's walk of Para he 

 caught 700 species of butterfly. One day he caught 46 butterflies 

 in the virgin forest, and among them were 33 separate species; on 

 the following day he caught 37, of which 33 were of different species ; 

 and these included 27 which he had not secured on the previous day. 

 This record says something as to the great variety of the tropical 

 fauna. Needless to say, the more untouched by man, the more rich 

 in variety is Nature. Multiplicity of form is the essential charac- 

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