THE GEOGRAPHICAL DISTRIBUTION OF ANIMALS. 



Animal life is distributed universally over the earth. Even the most 

 barren desert is traversed by some fleet-footed animal, and the ice- 

 covered circumpolar seas form the habitat of a varied animal world. 

 Nor has this world any limit, either above or below ; for over the ice- 

 clad peaks of the highest mountains the condor and the eagle still speed 

 their Boaring flight, and recent discoveries have shown the existence of a 

 rich world of the strangest animal forms inhabiting the nethermost 

 depths of the ocean. The closer we approach the equator, side by side 

 with the increasing luxuriance of the plant world (flora), the animal 

 world (fauna), too, grows richer in species and individuals. 



This would make it appear that the distribution of animals was 

 conditioned by climate. Up to a certain degree this is correct; for an 

 animal like the Polar bear, which is insensible to the Arctic cold, can" no 

 more exist in the tropics than animals belonging to the cat family, 

 which are very sensitive to cold, can live in the frigid zone. Climate, 

 however, is not the sole determinant factor in the distribution of animals, 

 for regions under the same degree of latitude (e.g., South America and 

 Africa), or even closely neighbouring each other {e.g., Celebes and Java), 

 may possess a widely different fauna ; whilst, on the other hand, the 

 fauna of regions of different degrees of warmth (e.g., that of Germany 

 and North Africa) may present a great similarity. 



Of very great importance in the distribution of animals is the fact that 

 the distribution of land and water has not ahoays been the same as it is now. 

 The connecting bridges between different land masses (e.g., between 

 Great Britain and the Continent) have disappeared, islands being formed ; 

 whilst in another direction tracts of land (e.g., the Sahara) have been 

 elevated out of the ocean. Nor has the climate of any particular region 

 always remained the same. Thus, in the Tertiary period lions existed 

 in Central Europe, whilst in the succeeding Glacial Age reindeer, Polar 

 bears, and other Arctic animals, flourished on our continent. 



32—2 



