204 



NORTH AMERICAN FAUNA 68 



The tagging of newborn or very young pups was discontinued 

 because the frightened mother, upon release, usually made several 

 long dives. It seemed probable that at least some of these young 

 pups may have died as a result of unusually long periods of 

 immersion. Also, several mothers refused to accept their helpless 

 pups when they were released and later failed to return for them. 



DISCUSSION 



To date the information from tagging is meager. Many of the 

 animals which were captured on land were there because they were j 

 ill or in weakened condition. For this reason, the rate of survival of 

 tagged animals is probably lower than for the population as a 

 whole. There is as yet no reason to believe, however, that the act 

 of tagging increased the mortality within the tagged segment of 

 the population as compared to the untagged segment (except when 

 mothers with small pups were captured). Disturbance of the 

 animals during tagging was brief and care was taken not to injure 

 them. The tag placed in the web of the hind flipper had no notice- 

 able effect on swimming. Marked animals, in the wild and in 

 captivity, ignored their tags, except that certain individuals 

 chewed the colored plastic flags attached to the metal tag. 



The data and general field observations lead to the following 

 tentative conclusions : ( 1 ) The home range of the female sea otter 

 during at least a 3-year period may include about 5 to 10 miles of 

 coastline. Soviet biologists found that the range from the "basic 

 station is 15 to 17 km. [9.3 to 10.5 miles]" (Nikolaev and Skalkin, 

 1963). (2) Animals tagged on one side of Amchitka did not move 

 around to the other side of the island (see Distribution and 

 Numbers). (3) Males may have a larger home range than females. 

 (4) Individual otters may use more than one of the traditional 

 hauling-out places. 



Additional information from tagged animals is found in sections 

 on "Age at Sexual Maturity," "Age Specific Mortality," and 

 "Juvenile Sex Ratio." 



Territoriality 



It is difficult to say whether territorialism exists in the sea 

 otter in the same sense that it does in other mammals. Many sea 

 otters, both male and female, share much of the same home range 

 within which the two sexes mingle to some degree. Also they may 

 segregate to haul out in traditionally established locations (see 

 Segregation of Sexes). | 



