MAMMALOGY MILLER 395 



skulls and which he unhesitatingly attributed to the effects of domes- 

 tication on one of the animals. Here, also, as in Darwin's case, was 

 an attempt at generalization without accurate systematic knowledge. 

 Had the ferret been compared not with the European polecat but 

 with an Asiatic species which is probably the actual wild ancestor, no 

 such differences would have been found ; in fact, the conclusion would 

 then have been reached that domestication had produced no per- 

 ceptible change. These concrete examples will serve as an index to 

 the importance of systematic study as the basis for all reasoning 

 about the history of life. 



There are many other subjects of broad general interest to whose 

 understanding the study of mammals may contribute. Why, for 

 instance, do the different mammals live where they now exist? 

 Every one knows in a general way, that each kind of mammal has its 

 home territory outside of which it cannot be found ; that polar bears 

 will not be seen swimming in the Amazon, and that elephants will not 

 be encountered in the woods of Maine. That the hippopotamus and 

 lion must be sought in Africa, the kangaroo in Australia, and the 

 walrus on the ice floes of the far north are facts within easy reach 

 of every reader ; but there are relatively few persons who know that 

 the lion and hippopotamus have left their bones in England, that ele- 

 phants have lived in all parts of the United States, that remains of the 

 walrus have been found as far south as Charleston, South Carolina, 

 and that camels and wild horses of many kinds have flourished in 

 America, some of them north of the Arctic Circle, only to become 

 extinct before the arrival of the white man. Equally unknown, per- 

 haps, is the fact that we have no undisputed evidence that kangaroos 

 and duckbills ever occurred anywhere but in Australia and in some 

 neighboring islands. 



The restriction of the ranges of wild animals occasioned by the 

 advance of civilization is now attracting so much notice that most 

 of us fail to realize how universally the same process is going on 

 without human interference, and how much more destructive to 

 particular forms of life is nature than man. Parts of the Sahara 

 were once wooded; with the drying up of these forests most of the 

 animals which inhabited them must have perished. A similar 

 process on a smaller scale seems to be now under way in the Kalahari 

 region of South Africa. Many animals which lived in the central 

 United States or in southern Europe under congenial arctic climates 

 during the Ice Age have been killed or driven far to the north by the 

 change to warm conditions which they could not bear. The mere 

 spreading of forests over grassy steppes has undoubtedly been 

 responsible for the disappearance of many more mammals than have 

 ever been exterminated by man. On the other hand we have recently 



