Philopatry and reproductive success in Bornean orang-utans (Pongo pygmaeus)

Authors

  • B. GOOSSENS,

    1. Biodiversity and Ecological Processes Group, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3TL, UK,
    2. Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, 88999 Kota Kinabalu, Sabah, Malaysia,
    3. Kinabatangan Orang-utan Conservation Project, PO Box 3109, 90734 Sandakan, Sabah, Malaysia,
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  • J. M. SETCHELL,

    1. Department of Biological Anthropology, University of Cambridge, Downing Street, Cambridge CB2 3DZ, UK,
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  • S. S. JAMES,

    1. Biodiversity and Ecological Processes Group, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3TL, UK,
    2. Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, 88999 Kota Kinabalu, Sabah, Malaysia,
    3. Kinabatangan Orang-utan Conservation Project, PO Box 3109, 90734 Sandakan, Sabah, Malaysia,
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  • S. M. FUNK,

    1. Durrell Wildlife Conservation Trust, Les Augres Manor, Trinity, Jersey JE3 5BP, UK Channel Islands,
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  • L. CHIKHI,

    1. UMR 5174 Evolution et Diversité Biologique, Bâtiment 4R3b2, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse cédex 4, France,
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  • A. ABULANI,

    1. Kinabatangan Orang-utan Conservation Project, PO Box 3109, 90734 Sandakan, Sabah, Malaysia,
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  • M. ANCRENAZ,

    1. Kinabatangan Orang-utan Conservation Project, PO Box 3109, 90734 Sandakan, Sabah, Malaysia,
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  • I. LACKMAN-ANCRENAZ,

    1. Kinabatangan Orang-utan Conservation Project, PO Box 3109, 90734 Sandakan, Sabah, Malaysia,
    2. Pittsburgh Zoo Society, Fellow Researcher, Pittsburgh Zoo, Pittsburgh, Pennsylvania, USA
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  • M. W. BRUFORD

    1. Biodiversity and Ecological Processes Group, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3TL, UK,
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Benoît Goossens, Fax: +44 (0)2920 87 4305; E-mail: goossensbr@cardiff.ac.uk

Abstract

Behavioural observations suggest that orang-utans are semi-solitary animals with females being philopatric and males roaming more widely in search of receptive partners, leading to the prediction that females are more closely related than males at any given site. In contrast, our study presents evidence for male and female philopatry in the orang-utan. We examined patterns of relatedness and parentage in a wild orang-utan population in Borneo using noninvasively collected DNA samples from animals observed to defecate, and microsatellite markers to assess dispersal and mating strategies. Surprisingly, resident females were equally as related to other resident females (mean rxy = 0.303) as resident males were to other resident males (mean rxy = 0.305). Moreover, resident females were more related to each other and to the resident males than they were to nonresident females, and resident males were more related to each other (and resident females) than they were to nonresident males. We assigned genetic mothers to 12 individuals in the population, while sires could be identified for eight. Both flanged males and unflanged males achieved paternity, similar to findings reported for Sumatran orang-utans.

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