ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 



241 



Pacific walruses differ from those in the eastern Canadian Arctic not only in 

 size but in other morphological characters, such as shape of snout and shape of 

 mandible, which presumably are genetically controlled (Allen 1880; Mansfield 

 1958fl; Pedersen 1962; F. H. Fay, unpublished data). The main concentrations 

 of these two populations are separated by at least 1,600 km. Although strays 

 from the Chukchi Sea occasionally reach the southeastern part of the Beaufort 

 Sea and Coronation Gulf, and those from the Canadian population occasionally 

 reach northern Banks Island (Harington 1966), there is little probability of 

 significant interchange between these two populations. 



The Pacific walrus population at present appears to be both physically and 

 reproductively isolated from all others. Its closer craniological resemblance to 

 the Laptev than to the Canadian walruses, in my opinion, suggests that its most 

 recent connections have been to the west, rather than to the east. 



History 



In an earlier report (Fay 1957), I briefly outlined the history of the Pacific 

 walrus population from the beginning of its commercial exploitation in the 18th 

 century to the middle of the present century. A more complete review of the 

 historical record is in preparation, but for the present, a brief synopsis will 

 suffice. 



Before the arrival of European man in the Bering Sea, the Pacific walrus 

 population must have comprised at least 200,000 animals, for it could not have 

 withstood the commercial harvests that followed had it been any smaller (Fay 

 1957). Its actual size, however, is unknown. 



More than 10,000 walruses were reported to have been harvested commer- 

 cially in some years during the late 18th to late 19th centuries (Sumner 1868; 

 Elliott 1886; Clark 1887; Petrof 1900; Arsen'ev 1927). The main products from 

 those harvests were ivory, oil, and hides. In the beginning, most of the animals 

 taken were from all-male herds summering in the southern part of the Bering 

 Sea, especially in Bristol Bay and on the Pribilof Islands. In a 2-year period, some 

 18 tons of walrus tusks (4,000-5,000 animals) were obtained on the Pribilofs 

 alone (Tikhmenev 1863). The Pribilof herds were nearly extirpated by the 

 beginning of the 19th century (True 1899), and the exploiters turned their 

 attention northward, into the pack ice zone. This change probably resulted in 

 larger numbers of females being taken thereafter, because the females tend to 

 stay with the ice. 



In the second half of the 19th century, the harvesting methods also changed 

 from the use of harpoon and lance (by which means nearly all of the animals 

 killed were retrieved) to shooting with rifles (by which many of those killed or 

 wounded were not retrieved; Clark 1887). I believe that this change (about 1866) 

 had a significant effect on the walrus population, for not only were larger 

 numbers taken and retrieved, but at least as many more were killed or wounded 

 that could not be retrieved. Nye (1879 in Allen 1880:768) and Petrof (1900) 

 estimated that the numbers of animals retrieved in the late 1800's amounted to 

 no more than one-fourth to one-third of the numbers killed. Because ivory was 

 the prime objective of those harvests, calves and other very young animals were 

 not taken. Hence, many dependent young were deprived of parental care. 



