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Jaeggi A.V.,University of Zurich | Stevens J.M.G.,Center for Research and Conservation | Van Schaik C.P.,University of Zurich
American Journal of Physical Anthropology | Year: 2010

Tolerant food sharing among human foragers can largely be explained by reciprocity. In contrast, food sharing among chimpanzees and bonobos may not always reflect reciprocity, which could be explained by different dominance styles: in egalitarian societies reciprocity is expressed freely, while in more despotic groups dominants may hinder reciprocity. We tested the degree of reciprocity and the influence of dominance on food sharing among chimpanzees and bonobos in two captive groups. First, we found that chimpanzees shared more frequently, more tolerantly, and more actively than bonobos. Second, among chimpanzees, food received was the best predictor of food shared, indicating reciprocal exchange, whereas among bonobos transfers were mostly unidirectional. Third, chimpanzees had a shallower and less linear dominance hierarchy, indicating that they were less despotic than bonobos. This suggests that the tolerant and reciprocal sharing found in chimpanzees, but not bonobos, was made possible by the absence of despotism. To investigate this further, we tested the relationship between despotism and reciprocity in grooming using data from an additional five groups and five different study periods on the main groups. The results showed that i) all chimpanzee groups were less despotic and groomed more reciprocally than bonobo groups, and ii) there was a general negative correlation between despotism and grooming reciprocity across species. This indicates that an egalitarian hierarchy may be more common in chimpanzees, at least in captivity, thus fostering reciprocal exchange. We conclude that a shallow dominance hierarchy was a necessary precondition for the evolution of human-like reciprocal food sharing. © 2010 Wiley-Liss, Inc. Source


Blooi M.,Ghent University | Pasmans F.,Ghent University | Longcore J.E.,University of Maine, United States | Spitzen-Van Der Sluijs A.,RAVON | And 2 more authors.
Journal of Clinical Microbiology | Year: 2013

Chytridiomycosis is a lethal fungal disease contributing to declines and extinctions of amphibian species worldwide. The currently used molecular screening tests for chytridiomycosis fail to detect the recently described species Batrachochytrium salamandrivorans. In this study, we present a duplex real-Time PCR that allows the simultaneous detection of B. salamandrivorans and Batrachochytrium dendrobatidis. With B. dendrobatidis- and B. salamandrivorans-specific primers and probes, detection of the two pathogens in amphibian samples is possible, with a detection limit of 0.1 genomic equivalent of zoospores of both pathogens per PCR. The developed real-Time PCR shows high degrees of specificity and sensitivity, high linear correlations (r2> 0.995), and high amplification efficiencies (>94%) for B. dendrobatidis and B. salamandrivorans. In conclusion, the described duplex real-Time PCR can be used to detect DNA of B. dendrobatidis and B. salamandrivorans with highly reproducible and reliable results.Copyright © 2013, American Society for Microbiology. All Rights Reserved. Source


Sanz C.M.,Washington University in St. Louis | Sanz C.M.,Wildlife Conservation Society | Deblauwe I.,Institute of Tropical Medicine | Tagg N.,Center for Research and Conservation | Morgan D.B.,Wildlife Conservation Society
Journal of Human Evolution | Year: 2014

It is an ongoing interdisciplinary pursuit to identify the factors shaping the emergence and maintenance of tool technology. Field studies of several primate taxa have shown that tool using behaviors vary within and between populations. While similarity in tools over spatial and temporal scales may be the product of socially learned skills, it may also reflect adoption of convergent strategies that are tailored to specific prey features. Much has been claimed about regional variation in chimpanzee tool use, with little attention to the ecological circumstances that may have shaped such differences. This study examines chimpanzee tool use in termite gathering to evaluate the extent to which the behavior of insect prey may dictate chimpanzee technology. More specifically, we conducted a systematic comparison of chimpanzee tool use and termite prey between the Goualougo Triangle in the Republic of Congo and the La Belgique research site in southeast Cameroon. Apes at both of these sites are known to use tool sets to gather several species of termites. We collected insect specimens and measured the characteristics of their nests. Associated chimpanzee tool assemblages were documented at both sites and video recordings were conducted in the Goualougo Triangle. Although Macrotermitinae assemblages were identical, we found differences in the tools used to gather these termites. Based on measurements of the chimpanzee tools and termite nests at each site, we concluded that some characteristics of chimpanzee tools were directly related to termite nest structure. While there is a certain degree of uniformity within approaches to particular tool tasks across the species range, some aspects of regional variation in hominoid technology are likely adaptations to subtle environmental differences between populations or groups. Such microecological differences between sites do not negate the possibility of cultural transmission, as social learning may be required to transmit specific behaviors among individuals. © 2014 Elsevier Ltd. Source


Etiendem D.N.,Free University of Brussels | Hens L.,Vlaamse instelling voor Technologish Onderzoek NV VITO | Pereboom Z.,Center for Research and Conservation
Ecology and Society | Year: 2011

Traditional beliefs associated with the Cross River gorilla (Gorilla gorilla diehli) in Lebialem Division, Cameroon, were studied to establish the usefulness of incorporating these local belief systems into the conservation strategy for this critically endangered species. A survey was conducted in 2007 in five villages to assess local perceptions of human-gorilla totemic kinship practices and taboos against hunting and against eating of gorillas. Villages were selected based on their proximity to Cross River gorilla (CRG) habitat, with a total of 184 interviewer-administered questionnaires completed during a 4-week period. Eighty-six percent of people agreed that gorillas were totems (personal spiritual helpers or counterparts) of people living in the village. People who believed in human-gorilla totemic kinship practice did not eat or hunt gorillas, and they wanted gorillas to be protected in order to protect the practice. Most (87%), of the interviewees declared their support for gorilla conservation. The main motivation was the belief that when gorillas are killed, the human totemic counterpart will die as a result. Because of these traditions, the hunting of gorillas is taboo in all five villages surveyed. On the other hand, gorilla parts play a direct role in traditional medicine, and gorilla bones are valued as ingredients for traditional medicine. Also, general awareness and adherence to local totemic practices was found to be declining, particularly among young people (18-25 years). Despite the imminent decline in value of belief systems that led to the establishment of the hunting taboo, this taboo is still in place and has discouraged the hunting of gorillas. Where law enforcement is weak or near inexistent, these traditional restrictions could be critical to the continuing survival of a gorilla population. Reviving and promoting beliefs and practices conducive to gorilla conservation could foster positive attitudes and behavior and have the potential to encourage local support and participation in communities. However, care must be taken when selecting practices to promote, as some (for example the use of gorillas in traditional medicine) could encourage the killing of animals. © 2011 by the author(s). Source


Behringer V.,Max Planck Institute for Evolutionary Anthropology | Hohmann G.,Max Planck Institute for Evolutionary Anthropology | Stevens J.M.G.,Center for Research and Conservation | Weltring A.,Max Planck Institute for Evolutionary Anthropology | Deschner T.,Max Planck Institute for Evolutionary Anthropology
Journal of Endocrinology | Year: 2012

Adrenarche is characterized by the onset of adrenal secretions of increasing amounts of dehydroepiandrosterone-sulfate (DHEA-S). While the function of adrenarche remains a matter of speculation, evidence suggests that the morphological and physiological changes related to it are restricted to humans and closely related primates. Within the primate order, adrenarche has been described only in humans and chimpanzees, but bonobos, the sister species of chimpanzees, have not yet been studied regarding the early ontogenetic changes such as adrenarche. While bonobos and chimpanzees share many morphological and behavioral characteristics, they differ in a number of behavioral traits, and there is a growing interest in terms of the physiological differences that can be linked to species-specific patterns of social behavior. In this study, we measured urinary DHEA-S levels to determine whether bonobos experience physiological changes that are indicative of adrenarche. We measured DHEA-S in urine using ELISA and analyzed its levels in the samples from 53 bonobos aged 1-18 years. Our results show that bonobos experience an increase in DHEA-S levels after 5 years of age, which is comparable with the patterns observed in humans and chimpanzees. This indicates that bonobos do undergo adrenarche and that the timing of onset is similar to that of the two Pan species. The extraction procedures described in this report demonstrate the use of urine for monitoring ontogenetic changes in DHEA-S excretion. If applicable to other species, the technique would facilitate more research on the evolutionary origin of adrenarche and other developmental processes. © 2012 Society for Endocrinology. Source

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