ECOLOGY AND BIOLOGY OF THE PAGIFIC WALRUS 



187 



700 

 600 

 500 

 400 

 300 

 - 200 



Z 100 



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OD 



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Adult 14-37 yr 



oo 



8 



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600 





Adolescent 



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500 





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400 





• 



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300 

 200 





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100 



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Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul 



Fig. 114. Weight of the testes per month in adult and adolescent and subadult Pacific 

 walruses. Each point represents the mean of the pair from one animal and indicates his- 

 tological findings of spermiogenasis (dots) versus recrudescence or retrogression (circles). 

 Curves were fitted visuallv. 



in "beginning stages" of spermiogenesis; the 11- to 19-year-old subadults and 

 young adults were spermiogenetic; and the older adults (up to 32 years) showed 

 signs of retrogression. Krylov (1967) observed that animals 10 to 15 years old 

 taken in April to June were potent, but the older adults were not. Of 712 males 

 examined by Krylov (1969) from July to October, only 1 (on 26 July) was potent. 



I found spermatozoa in the corpus epididymis mainly of animals that were 14 

 years old or older and principally from November to March (Table 30). In 

 animals 10 to 13 years old, spermatozoa were present less frequently and 

 somewhat later (December to Mav); I found none in specimens less than 10 years 

 old. 



