208 



NORTH AMERICAN FAUNA 68 



Segregation of Sexes 



Male and female sea otters at Amchitka habitually segregate 

 themselves and, almost always occupy distinct geographical areas 

 at all seasons. This condition first became apparent during obser- 

 vations when otters in various areas were counted and the numbers 

 of each sex recorded. Additional information was obtained when 

 otters were captured on beaches and when those dying of natural 

 causes were recovered. During harvesting operations in 1962 and 

 1963, more quantitative data on the degree of segregation became 

 available (tables 43 and 44). The terms "male area" and "female 

 area" refer to the geographical locations used predominantly (but 

 not exclusively) by each sex. Marakov (1965, p. 213) noted sexual 

 segregation among otters at Medny Island, Commander Islands, 

 U.S.S.R. 



FEMALE AREAS 



These are more numerous and less discrete than male areas 

 (fig. 83, map). Seven female areas are listed in table 43. At these 

 places the adult females usually haul out in favored sheltered 

 places near the extremities of points. In general, they appear less 

 bound to a limited hauling out location than the males. Certain 

 locations, however, such as St. Makarius Point W., Rifle Range 

 Point, and Constantine Point, are more favored than others. Tag 

 recoveries reveal that females may use more than one of the 

 favorite hauling grounds (see Home Range). The kill of adult 

 females reveals that they are generally distributed along the coast 

 when feeding. Many were taken a kilometer or more from favored 

 haul-out locations. Observations as well as data from the kill indi- 

 cate that females not only avoid the male haul-out locations but 

 also avoid the feeding habitat adjacent to them. Among 242 adult 

 otters killed in female areas, 93 percent were females. When 20 

 animals, not accompanied by a pup but in female areas, were 

 killed selectively (31 July to 3 August 1963) in an effort to take 

 males, only one male was obtained. This sample may indicate that 

 males constitute only 5 percent of the animals in female areas. 



MALE AREAS 



Three locations on the eastern half of Amchitka (fig. 83, map) 

 are used almost exclusively by males; the southeast tip of St. 

 Makarius Point (SMPE) about 800 m. of beach, the north beach 

 and tip of East Cape (ECN) about 500 m. of beach, and Crown 

 Reefer Point (CRP) about 600 m. of beach. Along each of these 



