226 



NORTH AMERICAN FAUNA 68 



Table 47. — Phases of reproduction in the female sea otter as shown by status 

 of ovaries and size of conceptus 



[Information from genital tracts collected from 1954 through 1963 is combined] 



Season of sample collection 



Jan.-Feb, 



Num- 

 ber 



Per- 

 cent 



Mar.-Apr. 



Num- 

 ber 



Per- 



cent 



May-Aug. 



Num- 

 ber 



Per- 

 cent 



Sept.-Dec. 



Total 



Per- num- 



cent ber 



Num 

 ber 



Unimplanted blastocyst- 



Conceptuses : 



Class 1 



Class 2 



Class 3 — - 



Class 4 



Class 5 



Total conceptuses- 



Total pregnant.. 

 Not pregnant 



Total tracts. 



26 



49 



50 



50 



69 



42 



16 



— 140 — 



25 — 



100 



0 

 0 

 0 

 0 

 0 



22 — 



84 



178 

 97 



275 



1 The 19 adult female sea otters taken between 31 July and 3 August 1963 were killed selec- 

 tively, mothers accompanied by pups were spared. Thus, the percentage of postpartum non- 

 pregnant specimens in this sample is less than it would have been if the kill had been non- 

 selective. 



2 See table 51 for more details. 



Table 48. — Frequency of primiparous and multiparous sea otters 



Primiparous Multiparous 



Period Total 



sampled examined Number Percent Number Percent 



1963 



15 Mar.-2 Apr 125 21 17 104 83 



31 July-3 Aug 12 2 17 10 83 



Total 137 23 114 



Table 49. — Uterine horn of pregnancy 



Uterine horn pregnant 



Right Left 



Period Specimens 



sampled examined Number Percent Number Percent 



Mar.-Apr 90 46 51 44 49 



May-Aug 7 3 43 4 57 



Total 97 49 51 48 49 



