234 



NORTH AMERICAN FAUNA 68 



mothers, may be some distance (it 50 m.) from them and thus not 

 associated with the mother by the hunter^s observations. Also, 

 large young may have recently become independent. 



Among the eight remaining nonpregnant females, four showed 

 no follicular activity or positive evidence of being post partum. 

 One of these was diseased. It possessed a large ovarian cyst 

 (31x15 mm.) The remaining four were multiparous (enlarged 

 uterine horns) but did not show evidence of being post partum 

 and appeared to be approaching estrus (follicles enlarged) or to 

 have recently ovulated. 



Summer sample 



Among 14 sexually mature sea otters taken between 31 July and 

 3 August 1963 at Amchitka, 5 (36 percent) were not pregnant. 

 Three of these were post partum. None was accompanied by a 

 pup. (As explained elsewhere, this collection was selectively taken 

 to exclude mothers accompanied by pups.) Two were multiparous 

 inactive but their reproductive tracts revealed no evidence of being 

 recently post partum (table 51). 



Fall sample 



Among 17 sexually mature females taken between 12 October 

 and 3 November, 13 (76 percent) were not pregnant. Among 

 these, eight (61 percent) were accompanied by young and one was 

 lactating, indicating that a pup had recently been lost. Of the five 

 remaining, three showed no follicular activity or indication of hav- 

 ing recently lost a pup. One showed follicular activity indicating 

 a proestrus condition (table 51). 



FIELD COUNTS 



An effort was made to record newly born young separately from 

 older dependent young. Because of variable field conditions, the 

 results were inconsistent and not useful to this study. Therefore, 

 all young with mothers were grouped as dependent animals. 



Counts were made in many areas but only in a consistent way 

 during all field seasons in the Constantine Harbor, Kirilof Point to 

 Kirilof Bay areas. After all of the data from several other areas 

 were studied, it became apparent that because of different con- 

 ditions in each area the results of counts in one area were not 

 comparable with those made in another. Also, counts made from 

 a cliff top cannot be compared with counts made from a dory. 

 Females with young among coastal rocks may be missed during an 



