38 GEOGRAPHICAL DISTRIBUTION. 



greatest abundance of its particular food, the reindeer-moss and 

 various lichens, without which it seems incapable of nourishing. 

 There can be little doubt that were individuals of the reindeer 

 transplanted to an elevated mountain region, such as the European 

 Alps, for example, where their own proper nourishment would be 

 again met with, they would thrive very nearly, if not fully, as well 

 as in their true homes north of the fifty-fifth or sixtieth parallel of 

 latitude. Indeed, even in their northern haunts the animals, at 

 least as is shown by the American species or variety, would seem to 

 be impatient of too great a cold, since in the winter they seek the 

 inner recesses of the forests for protection. 



Turning now to the class of birds, we find that similar illustra- 

 tions of climatic adaptation present themselves. Thus, the usually 

 considered ' ' tropical " or " equatorial " humming-birds are in reality 

 not such at all. While it is true that by far the greater number of 

 species belonging to this family are found within the region em- 

 braced within the tropics, yet the range of the family extends all 

 the way from Cape Horn (Eustephanus galeritus) to Sitka (Selas- 

 phorus rufus), or over a territory covered by no less than one hun- 

 dred and fifteen degrees of latitude. And even among the strictly 

 tropical forms many of them extend their range to the limits of 

 perpetual snow, some remaining in the cold region permanently. 

 The Oreotrochilus Chimborazo and O. Pichincha have their abode 

 in the equatorial peaks indicated by their respective specific names 

 at an elevation of no less than sixteen thousand feet or higher than 

 the summit of the Mont Blanc in a world of almost perpetual 

 snow, hail, and sleet. 13 In fact, the elevated Andean slopes are 

 much more thickly visited by humnring-birds than the deep low- 

 lands, no matter how luxuriantly these last may be clothed with 

 vegetation. 



The ostriches constitute another group of animals whose habitat 

 is popularly associated with the burning deserts of the Torrid zone. 

 While it is unquestionable that these birds do delight in just such 

 districts, it may yet be doubted whether the matter of climate has 

 very much to do with the selection of a region, since ostriches are, 

 or have been until recently, equally abundant in all parts of the 

 African continent, in the high table-lands as well as in the low- 

 lands, from Algeria to the Cape, and from the east to the west 

 coast, where the suitable desert conditions present themselves, and 



