88 NORTH AMERICAN FAUNA 68 



!Figure 49. — When closely approached, a cornered sea otter hisses, extends 

 its stiffened forelegs, and rears backwards as far as possible. No aggressive 

 behavior is displayed. (KWK 59-8-6) 



The period of dependence is unusually long. This was not ascer- 

 tained directly from known individuals, but indirectly through 

 various observations at Amchitka. Female reproductive tracts 

 from there indicate that the majority of young are born from early 

 spring to summer (see Reproduction in the Female). In the fall 

 and early winter, large juveniles are numerous. During the late 

 winter and early spring period of high mortality (March to May), 

 most of the juveniles that die v^eigh 20 to 30 lb. (9 to 14 kg.). 

 At the end of the annual **die-off" fev^ large juveniles can be 

 found alive. Observations during this period of juveniles crying 

 and swimming about, apparently in search of their mothers, plus 

 data compiled under ''Mortality Factors" and "Home Range" in- 

 dicate that most of these young animals are abandoned by mothers 

 in the period of stress caused by storms and depleted food re- 

 sources. 



It is assumed that this group of young, most of which were 

 dead by May, were the young that were born in the previous spring 



