ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 



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shoulder, from which it probably would have died eventually. However, its 

 death apparently had been precipitated by several, more recent injuries. These 

 included (1) extreme laceration of the hind flippers, including fracture of one 

 proximal phalange, (2) secondary contusion of the wounded shoulder, resulting 

 in fracture of the scapula and massive intramuscular hemorrhage, and (3) 

 contusion of the left hind limb and pelvis. 



The third specimen, a beach-cast adult female, was intact externally except 

 that its flippers were torn, and it had puncture wounds in the snout and in the 

 rump. These were not bullet wounds, for they had pierced only the skin with no 

 damage to the bones beneath. Internally, however, most of the ribs were broken 

 and there was widespread, deep intramuscular hemorrhage of the thorax. Some 

 of the fractured ribs had punctured the lungs. 



The last specimen was a beach-cast adult male, in which the hind flippers 

 were severely lacerated, with some phalanges partly exposed but not broken; it 

 also had numerous punctures and lacerations on the face. Internally, this animal 

 showed massive intramuscular hemorrhage, associated with fractures of both 

 scapulae, all of the ribs, the pelvis, and three sections of the spinal column. The 

 fractured ends of the ribs had punctured the lungs, releasing several liters of 

 blood into the thoracic cavity. 



The first and last specimens were in very fresh condition, having died no more 

 than 1 or 2 days before they were found. The second and third had been dead for 

 several months before necropsy but had been well preserved (frozen) in the beach 

 ice. In all cases, the juxtaposition of the hemorrhages and bone fractures 

 indicated that the injuries had been sustained while the animals were still alive, 

 rather than after death. The lack of external wounds (other than superficial 

 lacerations) on the torso adjacent to the internal injuries indicated further that 

 the internal damage had been caused by the animals being struck repeatedly by 

 one or more large, blunt objects with considerable percussive force. Finally, the 

 external lacerations and punctures appeared to have been caused by a series of 

 somewhat pointed teeth of about equal length, with tips 2 to 3 cm apart. The St. 

 Lawrence Islanders claim that such conditions are typical of walruses killed by 

 killer whales, which, according to traditional lore, disable their larger prey by 

 grasping the extremities with their teeth while other whales in the pod ram the 

 victim from below. 



The spacing between the parallel lacerations corresponded approximately to 

 the distance between tips of the teeth of immature killer whales (2.5 to 4 cm) and 

 was comparable to the spacing of parallel lacerations on carcasses of gray whales 

 {Eschrichtius robustus) known to have been killed by this predator. The internal 

 injuries also seemed consistent not only with the Eskimo lore but with reports by 

 Scheffer and Slipp (1948), Norris and Prescott (1961), and Rice (1968) that use of 

 the blunt snout as a battering ram for killing or disabling other marine animals is 

 part of the repertoire of aggressive behaviors of the killer whale. 



Some other, similar instances of mortality in walruses have been attributed to 

 other causes, perhaps incorrectly. Hanna (1920:121) examined five walrus 

 carcasses on St. Matthew Island and two on the Pribilofs and concluded that they 

 "had been crushed by the ice." Later, he examined three more on the Pribilofs 

 and determined that "in each case death had been caused by crushing of the body 

 cavity" (Hanna 1923:213). He surmised that these animals had been killed 



