THE SEA OTTER IN THE EASTERN PACIFIC OCEAN 125 



Where otters habitually use certain hauling-out areas, as they 

 do at Amchitka Island, a large number of fecal deposits may ac- 

 cumulate. Because these are composed primarily of the hard parts 

 of marine organisms (fig. 66), they may remain in recognizable 

 form for a number of weeks or, in well-protected locations, for 

 months. 



The analysis of fecal deposits from the Shumagin Islands and 

 from Amchitka are presented in tables 16 and 17. The fact that 

 sea urchins appeared in 95 percent of the droppings found on 

 Amchitka and only in 4 percent of those from the Shumagins is 

 significant. Sea urchins are available in the Shumagin Islands. 

 It thus appears that the sea otter may feed selectively. No evidence, 



Figure 66. — Contents of a large (286 g. dry weight) sea otter fecal deposit: 

 A — more than 100 varnished horse mussels (Musculus) (10 g.) ; these are 

 usually swallowed whole, the viscera are digested, and the valves pass 

 Intact through the gastrointestinal tract. B — fragments of the tests, spines, 

 and Aristotle's lanterns of an unknown number of green sea urchins 

 (Strongylocentrotus) (159 g.). C — broken shells and D — byssus threads, of 

 more than 40 horse mussels (Volsella) (117 g.). Sea urchins and large mus- 

 sels are crushed by the teeth, and parts of the test or shell are swallowed. 

 Specimen was collected on an Amchitka beach, 21 July 1956. The rule is 

 5 cm. (KWK 68-13-4) 



