Ecological Research

, Volume 19, Issue 2, pp 179–188 | Cite as

Mass mortality of Japanese macaques in a western coastal forest of Yakushima

  • Goro HANYA
  • Hideki SUGIURA
  • Sachiko HAYAKAWA
  • Shunji GOTO
  • Toshiaki TANAKA
  • Joseph SOLTIS
  • Naohiko NOMA
Original Articles

The mass mortality of wild Japanese macaques (Macaca fuscata Blyth) was observed in a warm temperate forest of Yakushima, southern Japan. Demographic changes of eight troops between August 1998 and August 1999 were studied and 56% of macaques disappeared from the five intensively studied troops. Mortality varied among troops: two troops became extinct, while another troop did not decrease in size. The rate of mortality of the other troops was between 33 and 80%. The variation in mortality among the troops was either the outcome of local concentrations of mortality or of intertroop competition. The rate of mortality decreased with increasing distance from the two extinct troops and with increasing troop size; these two factors could not be separated statistically. The direct cause of death was diagnosed as pneumonia for four out of five fresh carcasses. The fleshy fruit production in autumn 1998 was the lowest in 14 years, and macaques had relied on leaves earlier than in usual years. It was exceptionally hot and dry in the summer of 1998. The exceptionally poor fruit production and hot summer of this year, with the resulting shortage of high-quality foods, was consistent with the scenario that mass mortality was due to the poor nutritional conditions. However, the possibility that epidemics caused the mass mortality cannot be ruled out. Our findings proved that primates in a seemingly stable habitat experience fluctuations in demographic parameters under natural conditions.

Key words

disease intertroop competition Japanese macaque mass mortality Yakushima 


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Copyright information

© Blackwell Publishing Ltd 2004

Authors and Affiliations

  • Goro HANYA
    • 1
    • 6
    • 1
  • Hideki SUGIURA
    • 2
  • Sachiko HAYAKAWA
    • 2
  • Shunji GOTO
    • 2
  • Toshiaki TANAKA
    • 3
    • 7
  • Joseph SOLTIS
    • 4
  • Naohiko NOMA
    • 5
  1. 1.Department of Zoology, Graduate School of ScienceKyoto UniversityKyotoJapan
  2. 2.Primate Research InstituteKyoto UniversityInuyamaJapan
  3. 3.The Institute of Humanities and Social SciencesNihon UniversityTokyoJapan
  4. 4.National Institute of HealthPoolesvilleUSA
  5. 5.The University of Shiga PrefectureHikoneJapan
  6. 6.Primate Research InstituteKyoto UniversityInuyamaJapan
  7. 7.Primate Research InstituteKyoto UniversityInuyamaJapan

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