Life History: The Energy-Efficient Orangutan

SummaryA 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

Naturalistic Approaches to Orangutan Intelligence and the Question of Enculturation

Field studies have been, and continue to be, important contributors to theunderstanding of great ape cognition-especially with regard to questions of cognitiveecology or the key cognitive challenges in the evolution of primate intelligence. Theyare also critical to resolving a current debate, whether human enculturation boosts greatapes' cognition, because only studies of problem-solving in feral contexts can resolvethe question of whether abilities are higher in enculturated than non-enculturated greatapes. To this debate, this paper offers findings from observational field studies on freerangingrehabilitant orangutans' cognitive capabilities, as revealed in their foodprocessing and arboreal positioning, and on the possible social transmission of thatexpertise. These findings are combined with published findings on wild andenculturated great apes as a basis for assessing the effects of human enculturation ongreat ape cognition. This assessment joins several others in showing that free-ranginggreat apes independently achieve cognition of the same order of complexity asenculturated great apes, in concluding that claims for the effects of human enculturationare likely inflated, and in suggesting that the basis for the effectiveness of humanenculturation is that great apes normally "enculturate" themselves

Naturalistic Approaches to Orangutan Intelligence and the Question of Enculturation

Field studies have been, and continue to be, important contributors to theunderstanding of great ape cognition-especially with regard to questions of cognitiveecology or the key cognitive challenges in the evolution of primate intelligence. Theyare also critical to resolving a current debate, whether human enculturation boosts greatapes' cognition, because only studies of problem-solving in feral contexts can resolvethe question of whether abilities are higher in enculturated than non-enculturated greatapes. To this debate, this paper offers findings from observational field studies on freerangingrehabilitant orangutans' cognitive capabilities, as revealed in their foodprocessing and arboreal positioning, and on the possible social transmission of thatexpertise. These findings are combined with published findings on wild andenculturated great apes as a basis for assessing the effects of human enculturation ongreat ape cognition. This assessment joins several others in showing that free-ranginggreat apes independently achieve cognition of the same order of complexity asenculturated great apes, in concluding that claims for the effects of human enculturationare likely inflated, and in suggesting that the basis for the effectiveness of humanenculturation is that great apes normally "enculturate" themselves

Pantomime in great apes: Evidence and implications

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 Here we sketch evidence of pantomime in other great apes, methodological concerns and sophisticated cognitive capabilities that great ape pantomimes suggest

Tracking Deforestation, Drought, and Fire Occurrence in Kutai National Park, Indonesia

The dry lowland and mangrove forests of Kutai National Park (KNP) in Indonesia provide invaluable ecosystem services to local human populations (>200,000 in number), serve as immense carbon sinks to recapture anthropogenic emissions, and safeguard habitats for thousands of wildlife species including the critically endangered Northeast Bornean orangutan (Pongo pygmaeus morio). With recent reports of ongoing illegal logging and large-scale wildfires within this National Park, we sought to leverage the extensive catalogue and processing power of Google Earth Engine to track the rates and influences of forest loss within KNP over various time periods since 1997. We present estimates of forest loss from the Hansen Global Forest Change v1.9 dataset (2000–2021) which detected a loss of 15% (272 km2) of forest cover within KNP since 2000, half of which (137 km2) coincided with the El Niño-induced wildfires of 2015–2016. Using the MCD64A1 C6.1 MODIS dataset, we found significant spatial overlap between burned area and forest loss detections during the 2015–2016 period but identified considerable omissions in the burned area dataset over smallholder farms within KNP. We discuss the implications of deforestation in areas of primary orangutan habitat and how patterns of forest loss have influenced drought and fire dynamics within KNP. Finally, we compare time-series estimates of precipitation, the ENSO index, burned area, and forest loss to demonstrate that fire risk within KNP depends largely—but not exclusively—on drought severity, and that rates of non-fire (gradual) and fire-related (extreme) forest loss threaten the remaining forests of this National Park