496 



LAND ANIMALS 



slides, veritable rivers of rock, extend downward thousands of feet 

 in the arid Chilean Andes, fed by the splintering rock at the highest 

 levels. 



Rock-inhabiting animals are thereby favored, in so far as they are 

 otherwise adaptable to alpine conditions. Birds which nest in rocky 

 situations, such as birds of prey, and swifts, are abundant. Climbing 

 birds, with the exception of the wall creeper, Tichodroma muraria, 

 which has adapted itself to the rock and cliff habitat, are infrequent. 

 Alpine mammals, on the other hand, are likely to depend on climbing 



Vanessa 

 urticae 



'2 



Deciduous 

 Forest 



Coniferous 

 Forest 



Elfin 

 Wood 



Snow Zone 



i 



Cultivated 



Land 



Fig. 130. — Distribution of a snow butterfly, Maniola glacialis; an alpine form, 

 Pieris callidice ; and a lowland form accidental!}' reaching the snow zone, Vanessa 

 urticae. After Handschin. 



adaptations. Chamois, ibex, yak, and mountain sheep have strong 

 spreading hoofs. The American and Asiatic pikas and the chinchillas 

 of the Andes are abundant among rocks. The pikas depend greatly on 

 the rock slides for concealment and for situations in which they store 

 food. It must, of course, be remembered that rock-inhabiting animals 

 of many groups may be equally represented in the lowlands or may 

 not range at all into the mountain habitat. 



Zonal endemism. — The high mountain fauna may be classified 

 according to its vertical distribution into true alpine, tolerant alpine, 

 and accidental alpine forms. The true alpine faunal element consists 

 of the minority of animals which are confined to the alpine zone, such 

 as the snow finch (Montifringilla) , the wall creeper (Tichodroma) , the 

 marmot (Marmota) , and the chamois, in the Alps. Alpine-tolerant 

 animals are those which can live and develop in the alpine zone, but 

 range into it from lower levels. The Apollo butterfly, the viviparous 



