A study of orangutans' daily energy expenditure confirmed exceptionally slow metabolism. It suggests they evolved a lifestyle designed to minimize energy use. If so, shifting to a higher energy-use strategy may help explain how humans evolved.

An accurate estimate for orangutan nest decay time is a crucial factor in commonly used methods for estimating orangutan population size. Decay rates are known to vary, but the decay process and, thus, the temporal and spatial variation in decay time are poorly understood. We used established line-transect methodology to survey orangutan nests in a lowland forest in East Kalimantan, Indonesia, ...

In the present paper we introduce three new species of the genus Corymbitodes Buysson, 1904 from Nepal and from Northern India and provide the description of the male of C. kambaitiana Fleutiaux, 1942. No species of Corymbitodes was recorded from Nepal or India previously. The new species are C. bengalensis sp. nov. (India), C. chassaini sp. nov. (India), C. nepalensis sp. nov. (Nepal). C. kamb...

We assessed the ability of present-day environmental factors to explain the nonoverlapping range boundaries of Skistodiaptomus copepods in the northeastern USA. Variance partitioning using partial canonical correspondence analysis (CCA) attributed 21% of the variance in species occurrences to spatial location, 20% to spatially structured environmental variation, and 12% to environmental factors...

A captive juvenile Bornean orangutan (Pongo pygmaeus) died from an unknown disseminated parasitic infection. Deep sequencing of DNA from infected tissues, followed by gene-specific PCR and sequencing, revealed a divergent species within the newly proposed genus Versteria (Cestoda: Taeniidae). Versteria may represent a previously unrecognized risk to primate health.

Information about meat-eating behavior by wild orangutans (Pongo pygmaeus) is scant. The first article about such a case dates from 1981. Since 1989, seven incidents of adult female Sumatran orangutans eating slow lorises (Nycticebus coucang) have been witnessed. Three females from two study sites were involved. In three cases the females were seen catching the prey. There are too few cases to ...

Many social animals can discriminate between familiar and unfamiliar faces. Orangutans, however, lead a semi-solitary life and spend much of the day alone. As such, they may be less adept at recognizing conspecifics and are a good model for determining how social structure influences the evolution of social cognition such as facial recognition. The present study is the first report of whether o...

We recently demonstrated, by mining observational data, that forest-living orangutans can communicate using gestures that qualify as pantomime.1 Pantomimes, like other iconic gestures, physically resemble their referents.2,3 More elaborately, pantomimes involve enacting their referents.4 Holding thumb and finger together at the lips and blowing between them to mean "balloon" is one example.5 He...

Orangutans select different tactics for repairing failed communication, depending upon how well they are understood: they repeat signals if they are partially understood and switch tactics entirely if completely misunderstood.