Male vocal displays play an important role in sexual selection in many species. Despite abundant evidence in other vertebrate taxa, few studies have examined the energetic costs of primate calls. We are studying the long-calling behavior of Bornean orangutans (Pongo pygmaeus wurmbii) at Tuanan. For this study, we are combining behavioral, ecological, physiological, and acoustic data to determine the influence of health and energy status on male orangutan calling effort. This research was initiated by Dr. Wendy Erb in May 2013, and will continue until November 2015.
Collaborators: Dr. Wendy Erb, Dr. Erin Vogel
Energetic studies can provide valuable information regarding the life history of primates, as energy intake is required for growth, activity, maintenance, and reproduction. Bornean orangutans have the longest interbirth interval of any ape, averaging 7-9 years, but we still do not have a clear understanding of why juveniles depend on their mothers for such extended periods. Most of the few studies that have been conducted on orangutan energetics and physiology have taken place in the more common dipterocarp forests of Borneo. This project is examining caloric stress, energy balance, and body condition as variables in order to quantify the cost of motherhood on Bornean orangutans in a low-quality, non-masting habitat at the Tuanan Research Station. This research was initiated by Tim Bransford in June 2013, and will continue until 2015.
Collaborators: Timothy Bransford, Dr. Erin Vogel
In primates, population densities, movement behavior, and social organization have all been shown to correlate strongly with changes in forest structure and plant communities. While much of the focus of this work has been from the perspective of the primates themselves, it is well established that plant-animal interactions are dynamic two-way interactions, and that plant communities respond to the behavior of animals. In this study, we are assessing which aspects of the forest influence orangutan travel decisions, in particular, what orangutans actually know about the forest, and how they use this information to accomplish foraging goals. We are also investigating which nutrients are limiting at Tuanan, and whether orangutans are important for facilitating nutrient cycling in peat swamp forests, influencing the nutrients available to trees. This project hopes to shed light on the evolution of diet and memory in primates. Furthermore, by examining the potential of orangutans as nutrient cyclers and the services they provide for their ecosystem, this study provides an opportunity to assess the importance of orangutans for ecosystem health and functioning, and can provide a fresh take on the importance of conserving this species. This research was initiated by Shauhin Alavi in June 2013 and will continue until 2015.
Collaborators: Shauhin Alavi, Dr. Erin Vogel
Orangutan reintroduction programs have been established with the intention of releasing wild caught captive orangutans back into the wild. With approximately 600 orangutans currently housed, rehabilitation and release programs such as Nyaru Menteng have become critical to the survival of the species. Numerous studies have been conducted on wild orangutans; however, few have examined orangutan health while in a rehabilitation facility and fewer still have monitored the progress of orangutans once released. Using non-invasive methods we are investigating protein balance, immuno-responsiveness, and gastrointestinal parasitic infections in individuals at the rehabilitation center and those that have been released. We will compare these results with data from a long-term study of a wild population at the Tuanan Research Station. The first of its kind, this research stands to make important contributions to understanding Bornean orangutan rehabilitation and reintroduction. Its findings may suggest ways to improve the rehabilitation and reintroduction of ex-captives and thus the conservation of orangutans. This research was initiated by Liz Ballare in July 2013 and will continue until 2015.
Collaborators: Elizabeth Ballare, Dr. Erin Vogel
At the Tuanan Research Station, orangutans compete for fruit resources with four other primates, especially gibbons (Hylobates albibarbis), as well as other frugivorous animals, including hornbills (Family Bucerotidae). This study aims to determine the seasonal availability of fruits as well as the competition that occurs between orangutans and other frugivorous animals. This research was initiated by Fajar Saputra in August 2013 and will continue until 2014.
Collaborators: Fajar Saputra, Dr. Sri Suci Utami Atmoko
This research is examining immunological response, physiological stress, and actin-myosin breakdown in Bornean orangutans in relation to social stress and fluctuations in fruit availability. Through the analysis of observational data in combination with measures of inflammatory and catabolic stress, we hope to develop new tools for evaluating health in wild primates. Alysse conducted pilot research in Tuanan from August 2012 until March, 2013, during which time she collected urine samples, and data on dietary intake, and social behavior from wild orangutans. In the lab, she has begun validating methods of analyzing the urine for inflammatory bio-markers. Alysse will continue defining the parameters of her research and will return to Tuanan for the summer of 2014 to continue her pilot work, then return again in May of 2015 to work in the field collecting data for her dissertation.
Collaborators: Alysse Moldawer, Ricardo Ungaro, Dr. Erin Vogel
Odor is a key property of primate and human foods and this research focuses on quantifying fruit odor intensity using a field set-up designed and first used by Kim Valenta. Work is in the early phases at Tuanan.
Collaborators: Dr. Rob Scott, Tim Bransford, Kim Valenta