Table 2. — Stages of molt of the northern fur seal by age, sex, and month 

 (number of specimens in each stage of molt, excluding 35 pups). — Continued 



Stage of 

 molt 



Jan. 



Feb. 



Mar. Apr 



May 



June 



July 



Aug. 



Sept. 



Oct. 



Nov. 



Dec, 



Age over 5 ' 

 Male 



"Resting" seals in October and November have passed through the autumnal 

 molt of this year. 



^ Mean age of the seals in each sample is indicated below. Where the age of 

 a male is known only as "adult," "or bull," or "old," age 10 has been arbi- 

 trarily assigned. Where the age of a female is known only as "10+," age 12 has 

 been arbitrarily assigned. 



^ A "resting" seal in December has passed through the autumnal molt of this 

 year. The 13 "resting" seals in January are treated statistically as resting, 

 post-molt, each with a code value of 15. 



specimens were young ones; none older than 

 4 years. In January (up to the 23d) 8 of 53 

 seals taken were still molting. The eight were 

 females at least 10 years of age. Some of them 

 would have continued in molt into February or 

 March. On the other hand, no molting specimens 

 appear among 24 females older than 5 years 

 actually taken during February, nor any among 

 27 taken during March. 



Thus the overall molting period is certainly 

 8 months, and probably 9, Only in the months 

 of April and May could one be sure of finding 

 all seals in resting pelage. 



Duration of Molt in the Individual 



The data of the present study have been ob- 

 tained by killing seals from a large free popu- 

 lation. How, then, can one estimate the dura- 

 tion of molt in the individual? 



1. The duration of molt in any individual 

 must be less than the duration in a group of 

 which that individual is a member. In a fairly 

 homogenous group — the combined 2- and 3- 

 year-old males for the period July to Novem- 

 ber — 67 seals in a sample of 72 are in molt 

 (table 2), Obviously the average duration of 

 molt in the individual is less than 22 weeks. 



