Our flagship Orangutan Behaviour Project has been ongoing since 2003 when Borneo Nature Foundation Co-Director Dr Helen Morrogh-Bernard first started to habituate wild orangutans in the Sabangau Forest and collect data on their behaviour and ecology.
During the past 13 years we have followed over 100 different individuals and collected over 20,000 focal follow hours, making this one of the longest and largest studies of orangutan behaviour in their natural environment. These data have been collected by many people, principally our dedicated team of local field assistants and many international scientists, including seven PhD students.
Our primary objective for this project is to gain a better understanding about orangutan behaviour and ecology in a tropical peat-swamp forest, to compare with other populations in different habitats, and to see how they cope with the unique challenges that this habitat brings. All studies of mankind’s closest relatives help us get a better understanding of how human evolution was shaped by the environment, and we are regularly making new and exciting discoveries that reveal the orangutan’s great intelligence and problem-solving ability. We’re also using our data to inform conservation management plans, by understanding how orangutans cope – or in some cases, fail to cope – with the damaging and disruptive impacts of logging and fire. We understand how wild orangutans from a peat-swamp forest differ from those in other habitat types, which gives insight into how to structure the reintroduction of ex-captive apes into new populations.
When we first started, our main objectives were to habituate orangutans to human presence and then to build an understanding of their activity patterns and diet as a basis for understanding more complex questions. At this time the forest was still subject to illegal logging that had been rampant during the previous five years, so we set out to understand the impacts of human activities at this site, with special focus on illegal logging and orangutans’ response. We have also addressed specific questions concerning their feeding behaviour and energetics; their health in regards to parasite load; their ranging behaviour and we used genetic analyses to describe their relatedness and build a family tree of orangutans in Sabangau.
|We have discovered that orangutans are adaptable to changes in forest condition brought about by logging, provided that large feeding trees remain even if the canopy is badly-disrupted. We have found that orangutans in peat-swamp forest behave quite differently to those in dryland dipterocarp forests, by feeding for longer, travelling more in search of food and resting less than their cousins in the more seasonal forests. We have found clear evidence using genetic data that females are philopatric – they stay close to where they were born – whereas males disperse far away. Excitingly, we made the very first discovery of a fur-rubbing behaviour for self-medication, in which leaves of a certain species are chewed up and applied to the skin of the arms and legs to deal with muscle strains, in a behaviour similar to that practised by indigenous people in the same part of Borneo. Sabangau remains the only place where this behaviour has been observed.
As the project has developed so we have expanded our focus, but continue to collect a long-term record of behaviour, diet, reproduction and health, whilst adding new studies. Lead scientist Helen Morrogh-Bernard is particularly interested in the social behaviour of this solitary ape, identifying how social relationships are formed and maintained over large distances in a ‘Social Network’, with studies of male and female ranging and dispersal; the use and function of the long distance call; communications using gestures as well as sounds; relatedness and mother-infant interactions; and the development of social relationships during early adulthood.
“Our main objective will always be the conservation, monitoring and protection of Sabangau’s orangutan population to ensure its future survival”
These topics are of great interest to primatologists, and we are excited about addressing these questions during in the next few years, but our main objective will always be the conservation, monitoring and protection of this population to ensure its future survival. The recent fires in 2015 showed how important our presence in the forest is, as our team were the first to spot the fires, and immediately helped with putting them out. They are not just field assistants; they are protectors of the forest and the orangutans within it.