Reproductive success of Bornean orangutan males: scattered in time but clustered in space

• DOI: 10.1007/s00265-023-03407-6
• Publication Date: 2023-12-06T09:02:33Z
• Authors: Maria A. van Noor...; Laura R. LaBarge; Julia A. Kunz; Anna M. Marzec; Brigitte Spillmann; Corinne Ackermann; Puji Rianti; Erin R. Vogel; S. Suci Utami Atmoko; Michael Kruetzen; Carel P. van Schaik
• Keywords: Animal ecology; Philopatry; Pongo pygmaeus; Sire; Sexual dimorphism; Home range; Dominance (genetics)

The social and mating systems of orangutans, one our closest relatives, remain poorly understood. Orangutans (Pongo spp.) are highly sexually dimorphic females philopatric maintain individual, but overlapping home ranges, whereas males disperse, non-territorial wide-ranging, show bimaturism, with many years between reaching sexual maturity attaining full secondary characteristics (including cheek pads (flanges) emitting long calls). We report on 21 assigned paternities, among 35 flanged 15 unflanged, genotyped male Bornean orangutans pygmaeus wurmbii), studied from 2003 to 2018 in Tuanan (Central Kalimantan, Indonesia). All 10 infants born since mid-2003 an already identified sire were sired by males. adult ranged well beyond the study area (c. 1000 ha), their dominance relations fluctuated even within short periods. However, 5 sires had multiple offspring monitored area. Several over a period c. years, which overlapped siring periods other long-calling behavior indicated they not consistently dominant around time known conceptions. Instead, when seen area, spent most ranges whose sired. Overall, successful older more often resident than others.It is difficult assess reproductive success for individuals long-lived species, especially dispersing males, who cannot be throughout lives. Due extremely interbirth intervals, have male-skewed operational sex ratios thus intensive male-male competition every conception. Paternity analyses matched immature likely (only 50 males) natural population. Half these spread at least despite frequently ranging outside this Dominance was poor predictor success, but, consistent female tactics reduce risk infanticide, "sires" tended relatively high local presence, seems contribute males' success. results highlight importance large protected areas enable pattern dispersal ranging.The online version contains supplementary material available 10.1007/s00265-023-03407-6.