, Volume 53, Issue 2, pp 181–192

Factors affecting reproduction in rehabilitant female orangutans: young age at first birth and short inter-birth interval

  • Noko Kuze
  • David Dellatore
  • Graham L. Banes
  • Peter Pratje
  • Tomoyuki Tajima
  • Anne E. Russon
Original Article

DOI: 10.1007/s10329-011-0285-z

Cite this article as:
Kuze, N., Dellatore, D., Banes, G.L. et al. Primates (2012) 53: 181. doi:10.1007/s10329-011-0285-z


This study investigated the reproductive parameters of free-ranging rehabilitant female orangutans. We aimed to assess the factors that influence these parameters and provide information that could assist with the management of orangutan reintroduction programs. We analyzed the birth records of free-ranging female rehabilitants at Bukit Lawang, Bukit Tigapuluh, Sepilok, Camp Leakey, Kaja Island, Sungai Wain, and Meratus and compared them with reproductive parameters reported in wild and zoo populations. Females’ ages at first birth were 10.6–14.7 years, significantly earlier than those of wild and zoo orangutans. Computed inter-birth intervals (IBIs) calculated by the Kaplan–Meier method were 65.1–90.1 months; the values for Camp Leakey and Bukit Lawang rehabilitants were significantly shorter than those reported for wild Sumatran orangutans. Infant mortality rates were 18–61%; the values for Bukit Lawang and Sepilok were significantly higher than those reported for wild Sumatran and zoo orangutans. In rehabilitants, young ages at first birth and shorter IBIs may result from the high energy intake enabled by provisioning, although the possibility exists that they reflect underestimations of age on arrival at rehabilitation centers. The observed high infant mortality rate may reflect poor mothering skills due to human rearing and/or increased disease transmission. This study demonstrates that accelerated reproductive rates (younger age at first birth and shorter IBI) are common in provisioned rehabilitant females on both Sumatra and Borneo.


Orangutans Infant mortality rate Biased birth sex ratio Rehabilitation Reintroduction Provisioning 

Copyright information

© Japan Monkey Centre and Springer 2011

Authors and Affiliations

  • Noko Kuze
    • 1
  • David Dellatore
    • 2
  • Graham L. Banes
    • 3
    • 4
  • Peter Pratje
    • 5
  • Tomoyuki Tajima
    • 6
  • Anne E. Russon
    • 7
  1. 1.Wildlife Research Center of Kyoto UniversityKyotoJapan
  2. 2.Sumatran Orangutan Society/Orangutan Information CentreMedanIndonesia
  3. 3.Primate Immunogenetics and Molecular Ecology (PrIME) Research Group, Department of Biological AnthropologyUniversity of CambridgeCambridgeUK
  4. 4.School of Biological SciencesUniversity of AberdeenAberdeenUK
  5. 5.Frankfurt Zoological SocietyFrankfurtGermany
  6. 6.Graduate School of ScienceKyoto UniversityKyotoJapan
  7. 7.Psychology DepartmentGlendon College of York UniversityTorontoCanada

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