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Habituation, or the process of an animal becoming comfortable with human observers, is an essential part of wild primate observational studies. Despite the importance of this process, questions remain as to what counts as habituated for a particular species, how individuals and species react to humans, and how age-sex classes differ in these responses. To address these questions, we analyzed data from over 25 years of research on wild Bornean orangutans from Gunung Palung National Park, Indonesia, drawing from 8383 follows and 82,413 hours of observation. We categorized the degree of agitation with humans by totaling the number of alarm vocalizations, giving each follow a score of 1- 10. We then looked at behavioral measures using a GLMM to control for individual and food availability. This revealed that individuals with the highest vocalization scores spent a greater percentage of the day traveling (b=40.5, p < 0.0001), stayed higher in the canopy (b=16, p < 0.0001) and spent less time eating (b=205, p < 0.0001) than did animals that did not vocalize. Our analysis also revealed a less common, but frequently observed, alternative response to humans, which was to hide, often inside of a day nest, and emit no vocalizations. Individual orangutans were observed to switch between these two 'strategies' to get rid of human observers. We discuss the implications of this behavior as well as present evidence that different strategies in response to observers may vary between age-sex classes due to differing energetic demands. 

Habituation, or the process of an animal becoming comfortable with human observers, is an essential part of wild primate observational studies. Despite the importance of this process, questions remain as to what counts as habituated for a particular species, how individuals and species react to humans, and how age-sex classes differ in these responses. To address these questions, we analyzed data from over 25 years of research on wild Bornean orangutans from Gunung Palung National Park, Indonesia, drawing from 8,383 follows and 82,413 hours of observation. We categorized the degree of agitation with humans by totaling the number of alarm vocalizations, giving each follow a score of 1-10. We then looked at behavioral measures using a GLMM to control for individual and food availability. This revealed that individuals with the highest vocalization scores spent a greater percentage of the day traveling (b=40.5, p < 0.0001), stayed higher in the canopy (b=16, p < 0.0001) and spent less time eating (b=205, p < 0.0001) than did animals that did not vocalize. Our analysis also revealed a less common, but frequently observed, opposing response to humans, which was to hide, often inside of a day nest, and emit no vocalizations. Individual orangutans were observed to switch between these two ’strategies’ to evade human observers. We discuss the implications of this behavior as well as present evidence that the reaction of other orangutans mediates the response of focal individuals to humans, suggesting the importance of social learning in this behavior. 

Yayasan Palung (YP), a counterpart organization to the Gunung Palung Orangutan Conservation Project (GPOCP), focuses on several projects, including conservation research, sustainable livelihood programs, environmental outreach and education, and a monitoring and investigation unit. This proposed project will be a multi-community assessment to ascertain both the extent of orangutan-human interactions in villages in the vicinity of Gunung Palung National Park (GPNP) and to identify the impact of education and outreach efforts as well as areas where further programs could be beneficial. The project is currently in the design phase, with input on the methodology and survey instruments coming from YP staff, other local NGOs, and international collaborators, including doctoral students at Brunel University in London, University of Georgia in Athens, and Boston University. We are proposing to conduct interviews in 8-10 villages surrounding GPNP, composed of villages that have long-term relationships with GPOCP, others in which GPOCP has recently started sustainable livelihood and education programs, and others with which GPOCP has never worked. The goal will be to interview 30 people in each of these villages—25 through a door-to-door method, in which every fourth house will be approached, and 5 more targeted interviews with community leaders. All of these interviews will be semi-structured, with a survey composed of both closed and open-ended questions covering topics such as orangutan sightings and interactions (both positive and negative), perceptions of orangutans, use of the forest, and knowledge about conservation threats to humans, orangutans and other animals, and the forest ecosystem in general. To supplement these one-on-one semi-formal interviews, focus group-style interviews will also be conducted, to allow for a wider range of opinions and experiences to be heard and considered. Interviews will be led by trained YP staff, permitting for these individuals to gain skills in ethnographic methodology, and to build and continue relationships between YP staff and community members in the villages in which YP works. Funders: National Science Foundation (BCS-1638823); Conservation, Food and Health Foundation; ARCUS Foundation; 

The Gunung Palung Orangutan Project has conducted research on critically endangered wild Bornean orangutans (Pongo pygmaeus wurmbii) since 1994 in Gunung Palung National Park, West Kalimantan, Indonesia. A major goal of our broad-ranging research on orangutan behavior and ecology is to understand how the unique rainforest environment of Southeast Asia, characterized by dramatic changes in fruit productivity due to unpredictable mast fruiting, impacts orangutan behavior, physiology, and health. Much of our research has been devoted to the development of non-invasive techniques and an integrated biology approach – using hormonal assays, fecal processing, nutritional analysis, genetics, and behavioral ecology – and has led to an increased understanding of the ecological and evolutionary pressures shaping orangutan adaptations. Our results show that the extended life history and very slow reproductive rate of orangutans are adaptations to their environment. Orangutans in the Gunung Palung landscape, as elsewhere across Borneo and Sumatra, also face a series of conservation challenges, including extensive habitat loss and the illegal pet trade. We highlight how our investigations of orangutan health status, ecosystem requirements, and the assessment of orangutan density using ground and drone nest surveys have been applied to conservation efforts. We describe our project’s direct conservation interventions of public education and awareness campaigns, sustainable livelihood development, establishment of village-run customary forests, investigation of the illegal pet trade, and active engagement with Indonesian government organizations. These efforts, in concert with the development of local scientific and conservation capacity, provide a strong foundation for further conservation as orangutans face a challenging future.