Great Ape Trust

Des Moines, IA, United States

Great Ape Trust

Des Moines, IA, United States

Time filter

Source Type

Chancellor R.L.,Great Ape Trust | Chancellor R.L.,University of California at Davis | Rundus A.S.,Great Ape Trust | Rundus A.S.,West Chester University | Nyandwi S.,Great Ape Trust
International Journal of Primatology | Year: 2012

The increased number of primates living in fragmented habitats necessitates greater knowledge of how they cope with large-scale changes to their environment. Chimpanzees (Pan troglodytes) are exceptionally vulnerable to forest fragmentation; however, little is known about chimpanzee feeding ecology in fragments. Although chimpanzees have been shown to prefer fruit when it is available and fall back on more abundant lower quality foods during periods of fruit scarcity, our understanding of how chimpanzees use fallback foods in forest fragments is poor. We examined how chimpanzees cope with periods of fruit scarcity in Gishwati Forest Reserve, a disturbed montane rain forest fragment in Rwanda. We assessed seasonal changes in chimpanzee diet and the use of preferred and fallback foods through fecal and food site analysis. We also examined seasonal variation in nest group size and habitat use through marked nest censuses. We found that chimpanzees experienced a seasonal reduction in preferred fruit availability, which led to a seasonal diet shift to more fibrous foods, including several that functioned as fallback foods. Our results suggest that during periods of fruit scarcity the chimpanzees also reduced nest group size. However, we found that the chimpanzees did not alter their habitat use between high- and low-fruit seasons, which suggests that the small size of the forest limits their ability to change their seasonal habitat use. Consequently, fallback foods appear to be particularly important in small food-impoverished habitats with limited ranging options. © 2011 Springer Science+Business Media, LLC.


Tranquilli S.,University College London | Tranquilli S.,Max Planck Institute for Evolutionary Anthropology | Abedi-Lartey M.,Fauna Flora International | Amsini F.,Wildlife Conservation Society | And 43 more authors.
Conservation Letters | Year: 2012

A network of resource management areas (RMAs) exists across tropical Africa to protect natural resources. However, many are poorly managed and weakly protected. We evaluated how the lack of conservation effort influences the extinction risk of African great apes. We compiled information on presence/ absence of primary (law enforcement guards) and secondary (tourism, research) conservation activities and nongovernmental conservation organizations (NGOs) support for 109 RMAs over the last 20 years. Along with these data, we collected environmental and anthropogenic variables, including recent records of ape presence/absence for all RMAs. As expected, law enforcement as a primary activity was the best predictor of ape survival rather than tourism or research as secondary activities. Furthermore, long-term NGO support had a significant positive influence on ape persistence. Our study demonstrates the feasibility of evaluating the relative importance of different conservation activities, an important step towards more evidence-based approaches in ape conservation. © 2011 Wiley Periodicals, Inc.


Chancellor R.L.,Great Ape Trust | Chancellor R.L.,University of California at Davis | Langergraber K.,Max Planck Institute for Evolutionary Anthropology | Langergraber K.,Boston University | And 4 more authors.
International Journal of Primatology | Year: 2012

Many primate populations currently live in forest fragments. These populations are often unhabituated, elusive, and contain few individuals, making them difficult to study through direct observation. Noninvasive genetic methods are useful for surveying these unhabituated populations to infer the number and sex of individuals and the genetic diversity of the population. We conducted genetic analysis on 70 fecal samples from eastern chimpanzees (Pan troglodytes schweinfurthii) in Gishwati Forest Reserve, a forest fragment in western Rwanda. We genotyped all but two of these samples using 12 autosomal and 13 Y-chromosome microsatellite markers previously used in analyses of other chimpanzee populations. The genetic data show that these samples represent a minimum of 19 individuals (7 females, 12 males). However, because we may not have sampled all individuals in the population, we also performed mark-recapture analysis with the genetic data and found that the entire population likely numbers between 19 and 29 individuals. These results are consistent with opportunistic observations of at least 19 individual chimpanzees. Levels of variation at the Y-chromosome microsatellites were similar to those observed in other chimpanzee communities, suggesting that the chimpanzees in this forest are members of a single community. These results provide a baseline count of the number of male and female chimpanzees in the Gishwati Forest Reserve, and the data provide the potential for follow-up studies aimed at tracking individuals over time, thus aiding conservation management of this unhabituated population. © 2012 Springer Science+Business Media, LLC.


Walkup K.R.,Great Ape Trust | Shumaker R.W.,Iowa State University | Pruetz J.D.,Iowa State University
Journal of Comparative Psychology | Year: 2010

Preference for tools with either rigid or flexible properties was explored in orangutans (Pongo spp.) through an extension of D. J. Povinelli, J. E. Reaux, and L. A. Theall's (2000) flimsy-tool problem. Three captive orangutans were presented with three unfamiliar pairs of tools to solve a novel problem. Although each orangutan has spontaneously used tools in the past, the tools presented in this study were novel to the apes. Each pair of tools contained one tool with rigid properties (functional) and one tool with flimsy properties (nonfunctional). Solving the problem required selection of a rigid tool to retrieve a food reward. The functional tool was selected in nearly all trials. Moreover, two of the orangutans demonstrated this within the first test trials with each of the three tool types. Although further research is required to test this statistically, it suggests either a preexisting preference for rigid tools or comprehension of the relevant features required in a tool to solve the task. The results of this study demonstrate that orangutans can recognize, or learn to recognize, relevant tool properties and can choose an appropriate tool to solve a problem. © 2010 American Psychological Association.


PubMed | Great Ape Trust
Type: Comparative Study | Journal: Journal of comparative psychology (Washington, D.C. : 1983) | Year: 2010

Preference for tools with either rigid or flexible properties was explored in orangutans (Pongo spp.) through an extension of D. J. Povinelli, J. E. Reaux, and L. A. Thealls (2000) flimsy-tool problem. Three captive orangutans were presented with three unfamiliar pairs of tools to solve a novel problem. Although each orangutan has spontaneously used tools in the past, the tools presented in this study were novel to the apes. Each pair of tools contained one tool with rigid properties (functional) and one tool with flimsy properties (nonfunctional). Solving the problem required selection of a rigid tool to retrieve a food reward. The functional tool was selected in nearly all trials. Moreover, two of the orangutans demonstrated this within the first test trials with each of the three tool types. Although further research is required to test this statistically, it suggests either a preexisting preference for rigid tools or comprehension of the relevant features required in a tool to solve the task. The results of this study demonstrate that orangutans can recognize, or learn to recognize, relevant tool properties and can choose an appropriate tool to solve a problem.

Loading Great Ape Trust collaborators
Loading Great Ape Trust collaborators