The effects of forest phenology and floristics on populations of Bornean and Sumatran orangutans

Marshall, Andrew J.; Ancrenaz, Marc; Brearley, Francis Q.; Fredriksson, Gabriella; Ghaffar, N; Heydon, Matthew J.; Husson, Simon J.; Leighton, Mark; McConkey, Kim R.; Morrogh‐Bernard, Helen C.; Proctor, John; Schaik, Carel P. van; Yeager, Carey P.; Wich, Serge A.; Atmoko, Sri Suci Utami; Setia, Tatang Mitra

doi:10.1093/acprof:oso/9780199213276.003.0007

Cited by 88 publications

(76 citation statements)

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“…Among orangutans, Sumatran populations are much more gregarious than the Bornean populations (van Schaik, 1999;van Noordwijk et al, 2009), largely due to differences in forest productivity and food availability (van Schaik, 1999;Marshall et al, 2009). Most chimpanzee populations are more gregarious than orangutans (van Schaik et al, 2003c).…”

Section: Testing the Role Of Social Tolerancementioning

confidence: 99%

Orangutan tool use and the evolution of technology

Meulman

Schaik

2013

Tool Use in Animals

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Section: Testing the Role Of Social Tolerancementioning

confidence: 99%

Orangutan tool use and the evolution of technology

Meulman

Schaik

2013

Tool Use in Animals

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“…Based on recent data from long-term field studies it has become clear, however, that social organization including mating strategies differs among the orangutan species (reviewed in [67]). This is presumably due to habitat differences between the two islands, with higher abundance and lower temporal variability of food on Sumatra [37]. As a consequence of this, orangutan densities are higher on Sumatra and orangutans are more often found in close associations of several females than on Borneo [12,33,66].…”

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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“…We determined monthly fruit availability through 6 productivity plots (total area 2.4 ha), within which we enumerated, measured, and identified all trees (≥10 cm diameter at breast height [DBH]), figs, and lianas (≥3 cm DBH) (Harrison 2009;Marshall et al 2009;Morrogh-Bernard 2009). Around the middle of each month, we monitored each plot and recorded the presence/absence of ripe and unripe fruits, including only fruits eaten by orangutans in Sabangau ("orangutan fruits").…”

Section: Measuring Fruit Availabilitymentioning

confidence: 99%

“…Many contemporary orangutan populations live in nonmasting forests, however, which experience generally more consistent fruit availability (Marshall et al 2009;Morrogh-Bernard et al 2009;Vogel et al 2008). Thus, it is unclear whether the reported observations of energy shortfalls, and strong relationships between energy intake and fruit availability, in the masting forests of Gunung Palung (Knott 1998(Knott , 1999) also apply to orangutans in nonmasting habitats.…”

Section: Introductionmentioning

confidence: 99%

Orangutan Energetics and the Influence of Fruit Availability in the Nonmasting Peat-swamp Forest of Sabangau, Indonesian Borneo

2010

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Data on energy intake and the effects of fluctuations in fruit availability on energy intake for African apes, and orangutans in mast-fruiting habitats, indicate that orangutans may face greater energetic challenges than do their African counterparts. Comparable data on orangutans in nonmasting forests, which experience lower fluctuations in fruit availability, have been lacking, however, complicating interpretations. We conducted a 46-mo study of orangutan energetics in the nonmasting Sabangau peat-swamp forest, Indonesian Borneo. Sabangau orangutans experienced periods of negative energy balance apparently even longer than in mastfruiting habitats, as indicated by comparisons of observed energy intake with theoretical requirements and analysis of urinary ketones. Daily energy intake was positively related to fruit availability in flanged males, but not in adult females or unflanged males. This may represent different foraging strategies between age-sex classes and suggests that fruit availability is not always an accurate indicator of ape energy intake/balance. Urinary ketone levels were not generally related to fruit availability, daily energy intake, day range, or party size. This is probably due to low energy intake, and consequently high ketone production, throughout much of the study period. Comparisons with published results on African apes support the hypothesis that orangutans are unique among hominoids in regularly experiencing prolonged periods of negative energy balance. This has important effects on orangutan behavior and socioecology, and has likely been a key factor driving the evolutionary divergence of orangutans and African apes.

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The effects of forest phenology and floristics on populations of Bornean and Sumatran orangutans

Cited by 88 publications

References 0 publications

Orangutan tool use and the evolution of technology

Orangutan tool use and the evolution of technology

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

Orangutan Energetics and the Influence of Fruit Availability in the Nonmasting Peat-swamp Forest of Sabangau, Indonesian Borneo

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