122 



NORTH AMERICAN FAUNA 68 



mastication (seals and sea lions may, however, tear chunks from 

 a fish that is too large to swallow intact) . The sea otter apparently 

 captures fish with its paws and all fish flesh found in stomachs had 

 been torn into chunks that were crushed before swallowing. No 

 fish were swallowed whole. 



Thus, the sea otters' manner of capturing and eating fish is 

 unique among marine mammals. After the fish was brought to the 

 surface and killed by a crushing bite at or near its head, it was 

 held in the paws and chunks were torn from it, masticated to a 

 moderate degree and swallowed. Some chunks of fish found in 

 stomachs measured about 3x4x5 cm. Eating usually began at 

 the fish's tail and often all or most of the head (particularly of the 

 cottids) and viscera were discarded. Strong adult males clasped 

 the fish body firmly with the forepaws and extended claws, then, 

 starting at the anterior end ripped the skin with the canines and 

 incisors from first one side, then the other. The flesh and bones 

 were then rapidly eaten like a candy bar. Globefish, being scale- 

 less and having soft bones, were consumed almost in their entirety. 



In the Shumagin Islands four adult male and one adult female 

 sea otters were taken on 6 and 7 June 1960 at Simeonof Island 

 and one female on 11 June at Little Koniuji Island. Four stomachs 

 were empty. The stomach contents of two males are shown in 

 table 14. 



Of interest is the fact that among the contents of the two 

 stomachs which had a combined volume of 3.48 liters (3.7 qt.), 

 mostly clam meats, there were no scraps of clam shell. For this 

 reason, the species eaten could not be positively identified. Dr. 

 G. D. Hanna did, however, tentatively identify the large siphons 

 as belonging to the Washington clam (Schizothaerus nuttallii). 

 Perhaps this large clam was not removed from the sand bottom 

 or the shell could not be broken or opened by the otter. About 1 

 inch of the siphons appeared to have been bitten or ripped from 

 the clam bodies. A captive otter demonstrated that clams, even 

 large horse clams (Schizothaerus) , are cracked either against a 



Table 14. — Stomach contents of two male sea otters from Simeonof Island, 

 Shumagin Islands, Alaska 





Volume 





Specimen and food item 



(milliliters) 



Individuals 



KWK 60-6: Clam feet 



2,425 



155+ 



KWK 60-8: 







Large clam syphons 



- 844 



59 



Small clam feet 



206 



17 



Horse mussel 



5 



1 



Whelk operculum 



trace 



1 



Total 



3,480 



233 



