Sumatranorangutan

Staff and partners of SOCP regularly publish their work in leading scientific journals and on the web. Here you can find some of the latest results in orangutan research!

Hardus et al. 2012:
Behavioral, Ecological, and Evolutionary Aspects of Meat-Eating by Sumatran Orangutans (Pongo abelii)
Meat-eating is an important aspect of human evolution, but how meat became a substantial component of the human diet is still poorly understood. Meateating in our closest relatives, the great apes, may provide insight into the emergence of this trait, but most existing data are for chimpanzees. We report 3 rare cases of meat-eating of slow lorises, Nycticebus coucang, by 1 Sumatran orangutan mother–infant dyad in Ketambe, Indonesia, to examine how orangutans find slow lorises and share meat.
To get the wohle article, please send an e-mail to Serge Wich

Biological Conservation, December 2011:
Effects of logging on orangutan behavior
The human footprint is increasing across the world's natural habitats, causing large negative impacts on the survival of many species. In order to successfully mitigate the negative effects on species' survival, it is crucial to understand their responses to human-induced changes. This paper examines the effect of one such disturbance, logging, on Sumatran orangutans – a critically endangered great ape. Orangutan population densities may decrease or remain stable after logging, but data on the effects of logging on the behavior of individuals is scant. Here, we provide individual-level behavioral data based on direct observations in 2003–2008 at the Ketambe (Sumatra, Indonesia) research area (partly subject to intense selective logging) in order to assess responses of Sumatran orangutans to logging. Based on the results of this study, we provide recommendations for conservation research and guidelines for reduced-impact logging.
To get the wohle article, please send an e-mail to Serge Wich

Tropical Conservation Science Vol.4, 2011:
Which factors determine orangutan nests' detection probability along transects?
Effective conservation needs a solid baseline of animal distribution, density, and abundance data to base management strategies on and evaluate the effectiveness of conservation efforts on the species of interest.

PLOSone, June 2011:
Forest Fruit Production Is Higher on Sumatra Than on Borneo
Various studies have shown that the population densities of a number of forest vertebrates, such as orangutans, are higher on Sumatra than Borneo, and that several species exhibit smaller body sizes on Borneo than Sumatra and mainland Southeast Asia. It has been suggested that differences in forest fruit productivity between the islands can explain these patterns. Here we present a large-scale comparison of forest fruit production between the islands to test this hypothesis.

Nater 2011 Pongo phylogeography:
Sex-Biased Dispersal and Volcanic Activities Shaped Phylogeographic Patterns of Extant Orangutans (genus: Pongo)
The Southeast Asian Sunda archipelago harbors a rich biodiversity with a substantial proportion of endemic species. The evolutionary history of these species has been drastically influenced by environmental forces, such as fluctuating sea levels, climatic changes, and severe volcanic activities. Orangutans (genus: Pongo), the only Asian great apes, are well suited to study the relative impact of these forces due to their well-documented behavioral ecology, strict habitat requirements, and exceptionally slow life history.
To get the wohle article, please send an e-mail to Serge Wich

Silk et al. 2011:
Soils on exposed Sunda Shelf shaped biogeographic patterns in the equatorial forests of Southeast Asia
The marked biogeographic difference between western (Malay Peninsula and Sumatra) and eastern (Borneo) Sundaland is surprising given the long time that these areas have formed a single landmass.
To get the wohle article, please send an e-mail to Serge Wich

Meijaard et al. 2011:
Why Don't We Ask? A Complementary Method for
Assessing the Status of Great Apes
Species conservation is difficult. Threats to species are typically high and immediate.
To get the wohle article, please send an e-mail to Serge Wich

Lameira et al. 2010:
Review of geographic variation in terrestrial mammalian acoustic signals: Human speech variation in a comparative perspective
Human speech shows an unparalleled richness in geographic variation. However, few attempts have been made to understand this linguistic diversity from an evolutionary and comparative framework.

Meijaard et al. 2010:
Declining Orangutan Encounter Rates from Wallace to Present Suggest the Species was Once More Abundant
Hunting has been underestimated as a key causal factor of orangutan density and distribution. Species population declines have been more severe than previously estimated based on habitat loss only.

Pontzer et al. 2010:
Metabolic Adaptation for low energy throughput
Orangutans have an extremely low rate of daily energy use, which may be an evolutionary response to severe food shortages in their native rainforests.

Spehar et al. 2010:
Estimating Orangutan Densities using Standing Crop and Marked Nest Count Methods
Animal densities calculated using nest counts should be cautiously interpreted when used to make decisions about management.