Female reproductive strategies in orangutans, evidence for female choice and counterstrategies to infanticide in a species with frequent sexual coercion

Knott, Cheryl D.; Thompson, Melissa Emery; Stumpf, Rebecca M.; McIntyre, Matthew H.

doi:10.1098/rspb.2009.1552

Cited by 105 publications

(128 citation statements)

References 49 publications

(104 reference statements)

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“…In zoos, where usually a single adult male is housed permanently with one or more females, males do not face competition from other adult males. Although in this situation the challenge hypothesis would not predict higher levels of testosterone, the common occurrence of male aggression towards females in the mating context [30,45,63] may be indicative of relatively high testosterone levels in males housed permanently with females even in the absence of other adult males. Information on the variation in the mating behavior of the two species has accumulated over recent years and there is now growing evidence that males mate more often aggressively on Borneo than on Sumatra [63,67].…”

Section: Introductionmentioning

confidence: 99%

Species-specific patterns in fecal glucocorticoid and androgen levels in zoo-living orangutans (Pongo spp.)

Weingrill¹,

Willems²,

Zimmermann³

et al. 2011

General and Comparative Endocrinology

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In contrast to most primate species, including the other great apes, orangutans maintain a fission-fusion social system in the wild without being part of a stable community. In zoos, however, they are kept in permanent groups, usually consisting of one adult male and several females. In zoo orangutans, we predict higher levels of glucocorticoids and androgens in the Bornean species compared to its congener from Sumatra, due to the much more solitary lifestyle of Bornean orangutans and the apparent higher frequency of male aggression directed towards females in this species in the wild. To compare hormone levels of the two orangutan species, we validated a fecal glucocorticoid and a fecal androgen assay. Subsequently, fecal samples from a total of 73 female and 38 male orangutans housed in 29 European zoos were analyzed to investigate the effect of species, social group size, age and (for female glucocorticoid levels) reproductive state and the presence of adult males on fecal hormone metabolite concentrations. The results of linear mixed effect models indicate that both male and female Bornean orangutans show a steeper increase in glucocorticoid levels with increasing group size than Sumatran orangutans. We therefore conclude that Sumatran zoo orangutans are better able to adjust to social housing conditions than their Bornean congeners. In addition, our analyses reveal higher glucocorticoid levels in lactating females of both species compared to non-lactating and juvenile females. Concerning androgen levels in males, our analyses revealed significantly higher concentrations in Bornean than Sumatran orangutans. These differences in both glucocorticoid and androgen output between the two species of orangutan are presumably linked to ecological and behavioral differences and could possibly be attributed to phenotypic plasticity. However, given that we found interspecific differences in hormone excretion in captivity, where both species live under very similar conditions, we conclude that this variation has a genetic basis. a b s t r a c tIn contrast to most primate species, including the other great apes, orangutans maintain a fission-fusion social system in the wild without being part of a stable community. In zoos, however, they are kept in permanent groups, usually consisting of one adult male and several females. In zoo orangutans, we predict higher levels of glucocorticoids and androgens in the Bornean species compared to its congener from Sumatra, due to the much more solitary lifestyle of Bornean orangutans and the apparent higher frequency of male aggression directed towards females in this species in the wild. To compare hormone levels of the two orangutan species, we validated a fecal glucocorticoid and a fecal androgen assay. Subsequently, fecal samples from a total of 73 female and 38 male orangutans housed in 29 European zoos were analyzed to investigate the effect of species, social group size, age and (for female glucocorticoid levels) reproductive state and the presence of adult males on f...

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Section: Introductionmentioning

confidence: 99%

Species-specific patterns in fecal glucocorticoid and androgen levels in zoo-living orangutans (Pongo spp.)

Weingrill¹,

Willems²,

Zimmermann³

et al. 2011

General and Comparative Endocrinology

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“…Mating relations are different, with close male-female mating associations lasting weeks in Sumatra, but only days, if that, in northeast Borneo [27]. Forced matings are higher on Borneo [32], and perhaps the norm in northeast Borneo [30,33]. The development of the full complement of secondary sexual characteristics (with cheek flanges and long calls) is arrested in Sumatra, with some males waiting for at least two decades [25], but far less so on Borneo.…”

Section: Geographical Variation In Orang-utan Behaviourmentioning

confidence: 99%

The costs and benefits of flexibility as an expression of behavioural plasticity: a primate perspective

Schaik

2013

Phil. Trans. R. Soc. B

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Traditional neo-Darwinism ascribes geographical variation in morphology or in behaviour to varying selection on local genotypes. However, mobile and long-lived organisms cannot achieve local adaptation this way, leading to a renewed interest in plasticity. I examined geographical variation in orang-utan subsistence and social behaviour, and found this to be largely owing to behavioural plasticity, here called flexibility, both in the form of flexible individual decisions and of socially transmitted (cultural) innovations. Although comparison with other species is difficult, the extent of such flexibility is almost certainly limited by brain size. It is shown that brains can only increase relative to body size where the cognitive benefits they produce are reliably translated into improved survival rate. This means that organisms that are very small, face many predators, live in highly seasonal environments, or lack opportunities for social learning cannot evolve greater flexibility, and must achieve local adaptation through selection on specific genotypes. On the other hand, as body and brain size increase, local adaptation is increasingly achieved through selection on plasticity. The species involved are also generally those that most need it, being more mobile and longer-lived. Although high plasticity buffers against environmental change, the most flexible organisms face a clear limit because they respond slowly to selection. Thus, paradoxically, the largest-brained animals may actually be vulnerable to the more drastic forms of environmental change, such as those induced by human actions.

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“…Indeed, mean daily distance traveled for unflanged males was longest at 856.56 m, compared with 546.70 m for flanged males, 729.20 m for subadult females, and 694.45 m for adult females. Movement decisions by unflanged males could also be more variable due to their social plasticity and need to find mates while simultaneously avoiding flanged males (30,33), which could take precedence over energetic costs.…”

Section: Resultsmentioning

confidence: 99%

Canopy structure drives orangutan habitat selection in disturbed Bornean forests

Davies

Ancrenaz

Asner

2017

Proc. Natl. Acad. Sci. U.S.A.

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The conservation of charismatic and functionally important large species is becoming increasingly difficult. Anthropogenic pressures continue to squeeze available habitat and force animals into degraded and disturbed areas. Ensuring the long-term survival of these species requires a well-developed understanding of how animals use these new landscapes to inform conservation and habitat restoration efforts. We combined 3 y of highly detailed visual observations of Bornean orangutans with high-resolution airborne remote sensing (Light Detection and Ranging) to understand orangutan movement in disturbed and fragmented forests of Malaysian Borneo. Structural attributes of the upper forest canopy were the dominant determinant of orangutan movement among all age and sex classes, with orangutans more likely to move in directions of increased canopy closure, tall trees, and uniform height, as well as avoiding canopy gaps and moving toward emergent crowns. In contrast, canopy vertical complexity (canopy layering and shape) did not affect movement. Our results suggest that although orangutans do make use of disturbed forest, they select certain canopy attributes within these forests, indicating that not all disturbed or degraded forest is of equal value for the long-term sustainability of orangutan populations. Although the value of disturbed habitats needs to be recognized in conservation plans for wide-ranging, large-bodied species, minimal ecological requirements within these habitats also need to be understood and considered if long-term population viability is to be realized.Bornean orangutan | Carnegie Airborne Observatory | conservation | Light Detection and Ranging | movement ecology

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Female reproductive strategies in orangutans, evidence for female choice and counterstrategies to infanticide in a species with frequent sexual coercion

Cited by 105 publications

References 49 publications

Species-specific patterns in fecal glucocorticoid and androgen levels in zoo-living orangutans (Pongo spp.)

Species-specific patterns in fecal glucocorticoid and androgen levels in zoo-living orangutans (Pongo spp.)

The costs and benefits of flexibility as an expression of behavioural plasticity: a primate perspective

Canopy structure drives orangutan habitat selection in disturbed Bornean forests

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