250 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1945 



Disease. — Evidence clearly indicates that diseases have at times 

 been important factors in reduction of populations of wildlife. Dis- 

 eases and parasites, however, disseminate more freely in dense popu- 

 lations, so that the effect is to produce population fluctuations, or 

 cycles. Beyond this initial reduction of such populations, disease is 

 probably not as a rule an important factor in the extermination of a 

 species. 



WILDLIFE SPECIES THAT HAVE BECOME EXTINCT 



Although our own country in the past has abused its wildlife popu- 

 lation to the extent of exterminating several species, and has been 

 negligent in many ways in preserving vanishing forms, it has not been 

 alone in this. Before considering extinct North American animals, 

 let us glance at the headstones of the graves of some of the foreign 

 species. No attempt is made here to compile a complete list of extinct 

 animals of foreign countries, and only some of the more noteworthy 

 or conspicuous are included. 



In Europe, such an important mammal as the aurochs, ancestral 

 stock of some of our domestic cattle, which inhabited large areas of 

 central and southern Europe, and also northern Africa, passed into 

 the realm of vanished species in Poland in 1627. A few years later 

 the tarpan, an ancestor of the domestic horse found on the steppes of 

 southeastern Eussia, became extinct, although a close relative, 

 Przewalsky's or the Mongolian wild horse, still exists in small num- 

 bers in Mongolia. 



In Asia, Pere David's deer that formerly inhabited parts of North 

 China is extinct in the wild state. At the time of the Boxer Rebellion 

 in 1900, some 200 animals, all that remained in China of this species, 

 held in captivity in a park near Peking, were killed for food. For- 

 tunately, a few animals had previously been sent by the Duke of Bed- 

 ford to England, where about 50 are now maintained at Woburn. 

 Steller's sea cow, a huge manatee 30 feet long or more and weighing 

 upward of 3 tons, first brought to the attention of science in 1741, met 

 its doom in 1768 in supplying oil and food for man. This huge 

 manatee inhabited Copper and Bering Islands and possibly other 

 islands in Bering Sea. The Pallas cormorant, an interesting fish- 

 eating bird of the Commander and other Bering Sea islands, became 

 extinct in 1852. 



Among wildlife species that have been exterminated in Africa, the 

 first to go by the acts of modern man was the blue antelope, or 

 blaaubok, which disappeared in 1799 from South Africa. From 

 South Africa also there disappeared about 1875, through hunting, 

 the quagga, which resembled a donkey with zebralike stripes on its 

 cape and neck only. Burchell's zebra became extinct in South Africa 



