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Sherman J, Voigt M, Ancrenaz M, Meijaard E, Oram F, Williamson EA, Russon AE, Seaman DJI, Caurant C, Byler D, Wich SA. Outcomes of orangutan wild-to-wild translocations reveal conservation and welfare risks. PLoS One 2025; 20:PONE-D-24-27413. [PMID: 40106428 PMCID: PMC11970725 DOI: 10.1371/journal.pone.0317862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Accepted: 01/05/2025] [Indexed: 03/22/2025] Open
Abstract
Wild orangutans (Pongo spp.) are captured and moved (wild-to-wild translocated) primarily to prevent crop foraging or out of concern for orangutans' survival in fragmented habitat. Little is known about wild-to-wild translocation frequency, circumstances, and possible species conservation and individual welfare outcomes. We investigated orangutan wild-to-wild translocations in Indonesia from 2005 to 2022 using primarily data from public sources and consultation with practitioners. At least 988 wild orangutans were captured for translocation during the study period, including many reproductively valuable resident females and adult males removed from unprotected fragmented forests and forest patches. Data on health condition (n = 808) indicated 81.7% were reported as healthy at time of capture. Information on post-capture disposition (n = 268) showed that only 23% were translocated immediately. Mean estimated killing combined with reported translocation removals was calculated to affect 3.3% of orangutans in Kalimantan, and 11.6% in Sumatra, both higher than the threshold of mortality from human actions expected to drive populations to extinction. Negative impacts are likely compounded where multiple individuals are translocated from the same area, and for the Tapanuli orangutan (P. tapanuliensis), which has the smallest population and range of all orangutan species. Data on reasons for capture (n = 743) indicated most translocations (69%) were conducted to address crop foraging and orangutan presence in or around croplands and plantations. Forest cover analysis around 104 orangutan capture sites with high resolution spatial information indicated that deforestation levels in the year preceding capture were not significantly associated with likelihood of captures for translocation. To improve conservation outcomes, wild-to-wild translocations should be used only in exceptional circumstances. Most orangutans should instead be monitored and protected in situ by addressing conflicts and maintaining the forests, including forest fragments, they are using. When translocation is necessary, post-release survival and potential conservation impacts must be monitored.
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Affiliation(s)
- Julie Sherman
- Wildlife Impact, Portland, Oregon, United States of America
| | - Maria Voigt
- Wildlife Impact, Portland, Oregon, United States of America
| | - Marc Ancrenaz
- HUTAN, Sandakan, Sabah, Malaysia
- Borneo Futures, Bandar Seri Begawan, Brunei Darussalam
| | - Erik Meijaard
- Borneo Futures, Bandar Seri Begawan, Brunei Darussalam
| | | | | | - Anne E. Russon
- Department of Psychology, Glendon College, York University, Toronto, Canada
| | - David J. I. Seaman
- Durrell Institute of Conservation and Ecology, School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom
| | | | - Dirck Byler
- IUCN SSC Primate Specialist Group Section on Great Apes, c/o Re:wild, Austin, Texas, United States of America
- Re:wild, Austin, Texas, United States of America
| | - Serge A. Wich
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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van Noordwijk MA, LaBarge LR, Kunz JA, Marzec AM, Spillmann B, Ackermann C, Rianti P, Vogel ER, Atmoko SSU, Kruetzen M, van Schaik CP. Reproductive success of Bornean orangutan males: scattered in time but clustered in space. Behav Ecol Sociobiol 2023; 77:134. [PMID: 38076722 PMCID: PMC10700224 DOI: 10.1007/s00265-023-03407-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 11/13/2023] [Accepted: 11/15/2023] [Indexed: 12/22/2023]
Abstract
Abstract The social and mating systems of orangutans, one of our closest relatives, remain poorly understood. Orangutans (Pongo spp.) are highly sexually dimorphic and females are philopatric and maintain individual, but overlapping home ranges, whereas males disperse, are non-territorial and wide-ranging, and show bimaturism, with many years between reaching sexual maturity and attaining full secondary sexual characteristics (including cheek pads (flanges) and emitting long calls). We report on 21 assigned paternities, among 35 flanged and 15 unflanged, genotyped male Bornean orangutans (Pongo pygmaeus wurmbii), studied from 2003 to 2018 in Tuanan (Central Kalimantan, Indonesia). All 10 infants born since mid-2003 with an already identified sire were sired by flanged males. All adult males ranged well beyond the study area (c. 1000 ha), and their dominance relations fluctuated even within short periods. However, 5 of the 10 identified sires had multiple offspring within the monitored area. Several sired over a period of c. 10 years, which overlapped with siring periods of other males. The long-calling behavior of sires indicated they were not consistently dominant over other males in the area around the time of known conceptions. Instead, when they were seen in the area, the known sires spent most of their time within the home ranges of the females whose offspring they sired. Overall, successful sires were older and more often resident than others. Significance statement It is difficult to assess reproductive success for individuals of long-lived species, especially for dispersing males, who cannot be monitored throughout their lives. Due to extremely long interbirth intervals, orangutans have highly male-skewed operational sex ratios and thus intensive male-male competition for every conception. Paternity analyses matched 21 immature Bornean orangutans with their most likely sire (only 10 of 50 genotyped males) in a natural population. Half of these identified sires had multiple offspring in the study area spread over periods of at least 10 years, despite frequently ranging outside this area. Dominance was a poor predictor of success, but, consistent with female mating tactics to reduce the risk of infanticide, known "sires" tended to have relatively high local presence, which seems to contribute to the males' siring success. The results highlight the importance of large protected areas to enable a natural pattern of dispersal and ranging. Supplementary Information The online version contains supplementary material available at 10.1007/s00265-023-03407-6.
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Affiliation(s)
- Maria A. van Noordwijk
- Department of Evolutionary Anthropology, University of Zurich, Zürich, Switzerland
- Comparative Socio-Ecology Group, May Planck Institute of Animal Behavior, Konstanz, Germany
| | - Laura R. LaBarge
- Comparative Socio-Ecology Group, May Planck Institute of Animal Behavior, Konstanz, Germany
| | - Julia A. Kunz
- Department of Evolutionary Anthropology, University of Zurich, Zürich, Switzerland
- Institute des Sciences de l’Evolution Montpellier, University of Montpellier, Montpellier, France
| | - Anna M. Marzec
- Department of Evolutionary Anthropology, University of Zurich, Zürich, Switzerland
| | - Brigitte Spillmann
- Department of Evolutionary Anthropology, University of Zurich, Zürich, Switzerland
| | - Corinne Ackermann
- Department of Evolutionary Anthropology, University of Zurich, Zürich, Switzerland
| | - Puji Rianti
- Division of Animal Biosystematics and Ecology, Department of Biology, IPB University, Bogor, Indonesia
- Primate Research Center, IPB University, Bogor, Indonesia
| | - Erin R. Vogel
- Department of Anthropology, Center for Human Evolution Studies, Rutgers, The State University of New Jersey, New Brunswick, USA
| | | | - Michael Kruetzen
- Department of Evolutionary Anthropology, University of Zurich, Zürich, Switzerland
| | - Carel P. van Schaik
- Department of Evolutionary Anthropology, University of Zurich, Zürich, Switzerland
- Comparative Socio-Ecology Group, May Planck Institute of Animal Behavior, Konstanz, Germany
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zürich, Switzerland
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