I am, first and foremost, a field primatologist, and I either am
directly involved in or supervise a very diverse array of field studies
on New World primates. The major portion of my field research
takes place at two different sites in the Yasuní Biosphere Reserve in
Amazonian Ecuador – at the Proyecto
Primates Research Area, which I established in 1994 as a
Ph.D. student with Dr. Peter Rodman (UC Davis), and at the
Tiputini Biodiversity Station, located approximately 40 km
away. Both of these sites are home to a diverse primate
community consisting of 10 to 12 different species. Additionally, I collaborate on a number of projects involving fieldwork
in other New World sites outside of Ecuador.
Thank you to The Leakey Foundation, National Geographic, The Wenner-Gren Foundation, and National Science Foundation for funding numerous projects. Thank you also to the staff of both research stations and especially to the government of Ecuador.
Some of my ongoing field projects are described in more detail below. But first, I'd like to thank the project alumni (colleagues, students, and assistants listed below) that have been part of Proyecto Primates over the last few decades.
Behavior and Ecology of Ateline Primates:
Ateline primates – howler monkeys, woolly monkeys, spider monkeys, and muriquis – are a closely related group of New World monkeys that shared a common ancestor roughly 16 million years ago and that, today, manifest marked differences in foraging strategies and patterns of social organization, making them an excellent natural system for comparative study. Interestingly, however, all members of this clade of primates are characterized by a tendency for females to disperse from their natal social groups prior to reproduction and for some degree of male philopatry, which are both features of social organization that they share with the African great apes.
Prompted by this convergence with African hominoids (and, presumably, with our earliest human ancestors), much of my field research to date has centered on ateline primates. In my doctoral research and in follow-up work as a postdoctoral fellow, I focused on documenting the natural history, time allocation patterns, ranging behavior, diet, and foraging strategies of lowland woolly monkeys (Lagothrix poeppigii), particularly as they relate to conditions of changing resource abundance. The results of some of this work – including the unexpected significance of animal prey foraging for this otherwise largely frugivorous primate – are outlined in my publications on the ecological strategies and ranging behavior of woolly monkeys.
My more recent field work on atelines has focused on woolly monkey social behavior and population genetic structure and on comparing the social behavior, foraging strategies, seed dispersal behavior, and cognitive ecology of woolly monkeys with those of sympatric white-bellied spider monkeys (Ateles belzebuth) a closely-related primate that differs markedly in social organization. These various field projects, conducted in collaboration with several of my current graduate students, form the basis for a number of recent publications and presentations at professional meetings.
Evolution of Monogamy and Pair-Bonding in Primates
A second area of my ongoing fieldwork concerns several other members of the Yasuní primate community. Since 2002, I have been conducting a long-term study of the evolution of “monogamous” or "pair-bonded" social systems in primates using three species of New World monkeys – owl monkeys, titi monkeys, and sakis – as models. This work represents an international collaboration with Dr. Eduardo Fernandez-Duque (Fundación ECO, Argentina and CRES (Conservation and Research for Endangered Species), Zoological Society of San Diego), who studies one of these taxa (owl monkeys) at his field site in Argentina.
Monogamy is a rare social system in mammals, and the specific pressures leading to its evolution are still debated. Early hypotheses forwarded to explain the evolution of monogamy tended to fall into one of two classes. Some proposed that monogamy evolved in response to the need for biparental care in order to successfully rear offspring, while others envisioned monogamy as the default social system imposed upon males in cases where the dispersion of females makes it difficult for single males to successfully defend access to more than one. More recently, emphasis has turned to the role of direct mate guarding of individual females by males and to the importance of specific male-female bonds as an infanticide-prevention strategy, with "monogamy" then emerging as a tradeoff between the competing reproductive strategies of males and females. In this project, we are trying to evaluate these various hypotheses for the origin and maintenance of monogamy in primates using a comparative approach, collecting comparable behavioral, ecological, demographic, and genetic data on all three genera at my study site in Ecuador and on one of the taxa (owl monkeys) at study sites in both Ecuador and Argentina. As an additional component of this project, I am currently working in the laboratory to develop novel molecular genetic markers to allow paternity and population structure analyses for these monogamous species.
Tropical Forest Biodiversity and Phenology:
Primatologists interested in how ecological conditions shape the behavior and social strategies of their study subjects must also collect detailed data on the diversity, abundance, and distribution of resources of potential importance. Thus, a third area of my ongoing fieldwork focuses on documenting and understanding spatial patterns in plant diversity and temporal patterns of flowering and fruiting in neotropical forests. Since 1994, almost without interruption, my team has been collecting data every month on the phenological status of a large subset of the trees located in five hectares of botanical plots that were established at the onset of my studies. This now represents one of the largest databases of phenological information available for an Amazonian rainforest site. Additionally, some of my plots are periodically recensused to look at temporal changes in floristic composition and biomass. These data form a part of the Amazon Forest Inventory Network (RAINFOR) database, which compiles information from a large set of Amazonian rainforest sites for the purposes of monitoring the long-term dynamics and productivity of these forests in response to global climate change.
Juan Jose Bravo
Gaby de Luna
|Anand Dacier||Larry Dew|
|Mike Montague||Shelly Field||Jamille Heer|
|Delanie Hurst||Luke Matthews|
|Chelsea Kostrub||Chris Schmitt|
|Melisa Moreano||Ana Palma||Wilmer Pozo||Kristin Phillips|
|Brian Smith||Steph Spehar||Scott Suarez|
|Luke Ward||Monica Ramirez|