226 



NORTH AMERICAN FAUNA 74 



midline of the neck and back, about 30 cm apart. The fourth wound, on the 

 rump, did not resemble the others and may have been caused by some other 

 agent. This wound was triangular, about 20 cm on each side, encrusted with 

 dried blood and, apparently, devoid of epidermis and hair. A triangular piece of 

 the outer skin appeared to have been torn off, exposing the dermal layer. 



Mortality Due to Trampling 



Murie (1936), CoUins (1940), Cahalane (1947), and Burns (1965), have cited 

 cases of mass mortality of Pacific walruses, in which many "crushed" carcasses 

 were found high on the beach, well above the high tide line. The crushing was 

 believed to have been due to the animals having either hauled out in panic when 

 pursued by killer whales, or stampeded when frightened by low-flying aircraft. 

 In either event, they were thought to have piled up in the melee, crushing those 

 on the bottom of the pile. Although there is little question about the possible 

 presence of such frightening stimuli, or even about the animals' reactions to 

 them, the matter of some animals' being crushed has been open to question. 

 Gol'tsev (1968) remarked on the finding of numerous carcasses on hauling 

 grounds in the Soviet sector, but did not indicate the cause of death. Tomilin and 

 Kibal'chich (1975) also reported a large number of dead animals, including 21 

 calves trampled and two fetuses aborted during a stampede from the hauling 

 ground on Cape Blossom. \\'rangell Island. The stampede was caused by low- 

 flying aircraft. 



All of the reports from the American sector have been from the Punuk Islands, 

 which are situated off the eastern end of St. Lawrence Island (Fig. 1). The 

 animals involved were mosth' adult females and young of either sex. According 

 to the St. Lawrence Islanders, this mortalit}' takes place at Punuk in October to 

 December, when large numbers of walruses haul out there during the southward 

 migration. My obser\'ations there in January- and in March to July, as well as 

 those of several other biologists in March (B. P. Kelly, personal communication), 

 June (L. M. Shults, personal communication), and August (P. E. Tovey, 

 personal communication) have confirmed that li\'ing walruses are scarce or 

 absent at Punuk during those months, and that many carcasses are present, none 

 of them fresh. The only sightings of large numbers actually hauled out there and 

 of fresh carcasses have been in October and November (Burns 1965; G. C. Ray, 

 G. Pelowook, personal communication). 



My co-workers and I have visited the Punuk Islands fi\ e times in June and July 

 (1962, 1975, 1977-1979) and have inspected nearly 700 carcasses there. The 

 carcasses were all comparable in stage of deterioration to those known to have 

 beached on the nearby coast of St. Lawrence Island in autumn. Furthermore, 

 the size and state of dental development of the \oungest specimens, the 

 reproductive organs of the adults, and the cementum deposits on the teeth also 

 were consistent with those of specimens killed in October to December. A few of 

 the carcasses were rather flattened, the skin was dr\' and hard, and much of the 

 hair and epidermis had been lost. The flattened, hairless conditions had been 

 interpreted earlier as being indicati\'e of the animals having been crushed and 

 abraded by the passage of other walruses over them (Murie 1936), but eyewitness 

 accounts from the Eskimos indicated that the advanced decomposition and loss 

 of hair were due more to heating of the carcasses b\- contact with the living 



