, Volume 30, Issue 4, pp 571–575 | Cite as

Rise in age of sexual maturation in male Japanese monkeys at Takasakiyama in relation to nutritional conditions

  • Hideo Nigi
  • Shin-ichi Hayama
  • Ryuzo Torii
Short Communication


A few reports have suggested the possibility that feeding conditions might affect the sexual maturation of free-ranging Japanese monkeys in provisionized troops. In the present study, the sexual maturation of male monkeys at Takasakiyama in 1984, nine years after the start of restriction of artificial feeding, was examined externally and histologically and the results were compared with data obtained in 1971, when artificial foods were abundantly given. Spermatogenesis was not observed in any of the males under 4.5 years old in the present study, whereas it was noted in some premature 3.5-year-old males and in all males over 4.5 years old in the 1971 study. The age of sexual maturation thus rose by one or more years over the 13-year period from 1971 to 1984. The lag in sexual maturation of the males at Takasakiyama in 1984 could have been induced by the restriction of artificial feeding.

Key Words

Sexual maturation Japanese monkey Spermatogenesis Nutritional conditions 


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  1. Mori, A., 1979. Analysis of population changes by measurement of body weight in the Koshima troop of Japanese monkeys.Primates, 20: 371–397.Google Scholar
  2. Nigi, H., 1975. Sexual maturity of male Japanese monkeys (Macaca fuscata) in Shiga A troop.Physiol. & Ecol., 16: 47–53. (in Japanese)Google Scholar
  3. ————, 1982.The Japanese Monkey: Its Physiology of Sex. Dobutsu-sha, Tokyo, Japan. (in Japanese)Google Scholar
  4. ————,T. Tiba, S. Yamamoto, Y. Floescheim, &N. Ohsawa, 1980. Sexual maturation and seasonal changes in reproductive phenomena of male Japanese monkeys (Macaca fuscata) at Takasakiyama.Primates, 21: 230–240.Google Scholar
  5. Sugiyama, Y. &H. Ohsawa, 1988. Population dynamics and management of baited Japanese monkeys at Takasakiyama.Primat. Res., 4: 33–43. (in Japanese)Google Scholar
  6. Tiba, T. &H. Nigi, 1975. Unregelmässig aufgebaute Zellgemeinshaften des Samenepithels beim free-ranging Japanischen Makak (Macaca fuscata) in der Paarunsgzeit.Primates, 16: 379–398.CrossRefGoogle Scholar
  7. ———— & ————, 1980. Jahreszeitliche Schwankung in der Spermatogenese beim “free-ranging” Japanischen Makak (Macaca fuscata).Zool. Anz., 204: 371–387.Google Scholar

Copyright information

© Japan Monkey Centre 1989

Authors and Affiliations

  • Hideo Nigi
    • 1
  • Shin-ichi Hayama
    • 1
  • Ryuzo Torii
    • 2
  1. 1.Department of Wild Animal MedicineNippon Veterinary and Zootechnical CollegeTokyoJapan
  2. 2.Institute for Experimental AnimalsShiga University of Medical ScienceShigaJapan

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