THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 107 



I thus inferred that she relied primarily on her tactile ability to 

 find food. 



Sight under water, however, is apparently sometimes used in 

 locating food. Captive otters on Amchitka often searched the 

 bottom of their pool by swimming on the surface, head submerged. 

 Food items on the bottom were quickly located visually in this 

 manner and retrieved. 



The vibrissae may also aid in the search for food. Captive otters, 

 having an abundance of easily located food, abrade the vibrissae 

 to a minor degree ; they may reach a length of 10 to 12 cm. (fig. 59) . 

 The vibrissae of wild otters may be worn off short, to a length of 

 about 1.5 to 2.5 cm. Presumably the abrasion occurs during the 

 search for food among rocks. 



Figure 59. — A captive otter pounds a clam (Protothaca) on the cement edge 

 of her pool. This otter came from Amchitka where breaking shells of food 

 organisms by pounding was not observed. The whiskers of captive otters 

 grow long, as illustrated here. In the wild the whiskers are usually abraded 

 and short. Presumably wear occurs during the search for food among 

 rocks. (KWK 57-24^16) 



