278 



NORTH AMERICAN FAUNA 68 



Blindness 



Otherwise healthy sea otters blind in one eye were occasionally 

 seen at Amchitka. No wild otter blind in both eyes was observed. 

 The cornea of the left eye of a yearling otter (Susie) was punctured 

 near the center by a tiny ''pinhole" when she was captured at 

 Amchitka in 1955. Within weeks the eye became cloudy and 

 eventually completely blind. About 2 years before her death in 

 1961 the right eye also became cloudy (presumably aifected by the 

 other blind eye) and total blindness resulted. Because she had 

 learned the topography of her enclosure well before losing her 

 sight, she appeared to experience no difficulty in finding her food 

 and her way about her quarters. 



Intussusception 



Blocking of the small intestine by the intestine "swallowing" 

 itself occurred in three captive otters. These animals were held in 

 unsatisfactory cages without sufficient water for immersion. The 

 animals appeared to experience emotional stress, as evidenced by 

 frequent vocalization for one or more days before death occurred. 



Predation 



No information exists to indicate that predation by animals 

 (other than man) on the sea otter is an important factor in its 

 population dynamics. Available information on predation is pre- 

 sented below : 



SHARKS 



It is beyond question that some sea otters are killed by sharks. 

 Snow (1910, p. 278) states: 



Wounded otters I have taken on a few occasions, but they had been bitten by 

 sharks, as I know from finding several of the sharks' teeth broken off in 

 wounds. 



Orr (1959) discovered the broken tooth of a great white shark 

 (Carcharadon carcharias) in the lacerated body of a sea otter 

 found dead at Pebble Beach, Calif. He considered that one other 

 otter he examined definitely died from shark wounds and that 

 several others found dead and bearing lacerations may have died 

 as a result of shark attacks. That skin divers may have inflicted 

 fatal wounds with spears, although a possibility, must be con- 

 sidered an opinion to be carefully weighed, since no proof that this 



