INTRODUCTION 9 



the world has lost, through extinction, about 106 known forms of 

 mammals. About 28 percent of these are subspecies of still existing 

 species, but the full species completely and irretrievably lost number 

 approximately 77. 



Between A. D. 1 and 1800, about 33 mammals are more or less 

 definitely known to have become extinct (see list, pp. 17-18) . Each 

 half -century period since 1800 shows a steadily increasing rate of 

 extinction. The last 100 years have witnessed the passing of about 

 67 percent of the 106 extinct forms. In the past 50 years approxi- 

 mately 38 percent as many forms have been exterminated as in all 

 previous recorded history. At the present time more than 600 others 

 require consideration as vanishing or threatened forms. It is well 

 within the bounds of possibility that during the next hundred years 

 we may be extinguishing this group at the approximate rate of one 

 form per year. 



In seeking the causes of this world-wide tragedy, it becomes ap- 

 parent that conditions vary widely over the different regions of 

 the globe, although there is a single major underlying factor nearly 

 throughout. 



For the purposes of the present inquiry, we may here pass briefly 

 in review the major regions that are covered in this volume: 

 Australia, the Malay Archipelago, Asia, Europe, Africa, and Mada- 

 gascar. 



AUSTRALIA 



Conditions in Australia are peculiar and exceptional, owing to 

 the fact that its unique native mammalian fauna is predominantly 

 marsupial, and so lowly organized as to be quite unfitted for coping 

 with certain exotic and aggressive species introduced by civilized 

 man. The chief of these are the European Red Fox, the Domestic 

 Cat, the European Rabbit, the House Rats, and the House Mouse. 

 Further competition results from the encroachment of hosts of 

 sheep and cattle upon the ancestral grazing grounds of the her- 

 bivorous marsupials. An apparently minor predatory role is played 

 by the Dingo (Cams dingo), which was presumably introduced by 

 aboriginal man. 



The Fox and the Cat (which has become feral in large numbers) 

 have long been active in the direct extermination of the smaller and 

 comparatively helpless marsupials. The Rabbit, in millions, operates 

 indirectly but no less effectively by overrunning the land, occu- 

 pying all available burrows, and depriving the herbivorous mar- 

 supials (even such large species as the kangaroos) of the food 

 necessary to their existence. The introduced rats and mice usurp 

 the habitats of the native species. Even sanctuaries are not proof 

 against such enemies as the foregoing. 



