Are the long calls of Bornean orangutans costly signals of male health and energy status?
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
An interdisciplinary approach to understanding the energetic costs of motherhood in wild Bornean orangutans
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
Nutrients in and nutrients out: diet, cognition, and nutrient cycling in orangutan habitats
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
Protein balance, immuno-responsiveness, and gastrointestinal parasites in rehabilitated and released orangutans
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
Orangutan food competition at the Tuanan Research Station, Central Kalimantan
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
A non-invasive methodology for monitoring wild orangutans' physiological and endocrinnological responses to stressors
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
Fruit odor intensity and selection in primates
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