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Parsons M.B.,Emory University | Parsons M.B.,Centers for Disease Control and Prevention | Travis D.,University of Minnesota | Lonsdorf E.V.,Franklin And Marshall College | And 7 more authors.
PLoS Neglected Tropical Diseases | Year: 2015

Cryptosporidium is an important zoonotic parasite globally. Few studies have examined the ecology and epidemiology of this pathogen in rural tropical systems characterized by high rates of overlap among humans, domesticated animals, and wildlife. We investigated risk factors for Cryptosporidium infection and assessed cross-species transmission potential among people, non-human primates, and domestic animals in the Gombe Ecosystem, Kigoma District, Tanzania. A cross-sectional survey was designed to determine the occurrence and risk factors for Cryptosporidium infection in humans, domestic animals and wildlife living in and around Gombe National Park. Diagnostic PCR revealed Cryptosporidium infection rates of 4.3% in humans, 16.0% in non-human primates, and 9.6% in livestock. Local streams sampled were negative. DNA sequencing uncovered a complex epidemiology for Cryptosporidium in this system, with humans, baboons and a subset of chimpanzees infected with C. hominis subtype IfA12G2; another subset of chimpanzees infected with C. suis; and all positive goats and sheep infected with C. xiaoi. For humans, residence location was associated with increased risk of infection in Mwamgongo village compared to one camp (Kasekela), and there was an increased odds for infection when living in a household with another positive person. Fecal consistency and other gastrointestinal signs did not predict Cryptosporidium infection. Despite a high degree of habitat overlap between village people and livestock, our results suggest that there are distinct Cryptosporidium transmission dynamics for humans and livestock in this system. The dominance of C. hominis subtype IfA12G2 among humans and non-human primates suggest cross-species transmission. Interestingly, a subset of chimpanzees was infected with C. suis. We hypothesize that there is cross-species transmission from bush pigs (Potaochoerus larvatus) to chimpanzees in Gombe forest, since domesticated pigs are regionally absent. Our findings demonstrate a complex nature of Cryptosporidium in sympatric primates, including humans, and stress the need for further studies.


Gilby I.C.,Duke University | Brent L.J.N.,Duke University | Wroblewski E.E.,Stanford University | Rudicell R.S.,University of Alabama at Birmingham | And 3 more authors.
Behavioral Ecology and Sociobiology | Year: 2013

Coalitionary aggression occurs when at least two individuals jointly direct aggression at one or more conspecific targets. Scientists have long argued that this common form of cooperation has positive fitness consequences. Nevertheless, despite evidence that social bond strength (which is thought to promote coalition formation) is correlated with fitness in primates, cetaceans, and ungulates, few studies have directly examined whether coalitionary aggression improves reproductive success. We tested the hypothesis that among free-ranging chimpanzees (Pan troglodytes schweinfurthii), participation in coalitionary aggression increases reproductive output. Using 14 years of genetic and behavioral data from Gombe National Park, Tanzania, we found that coalitionary aggression increased a male's chances of (A) siring offspring, compared to other males of similar dominance rank, and (B) ascending in rank, a correlate of future reproductive output. Because male chimpanzees form coalitions with many others within a complex network, we used social network analysis to identify the types of connections correlated with these fitness benefits. The beneficiaries of coalitionary aggression were males with the highest "betweenness"-that is, those who tended to have coalition partners who themselves did not form coalitions with each other. This suggests that beyond simply recognizing third-party relationships, chimpanzees may use this knowledge to choose coalition partners. If so, this is a significant step forward in our knowledge of the adaptive value of social intelligence. Regardless of mechanism, however, this is the first evidence of genetic benefits of coalitionary aggression in this species, and therefore has important implications for understanding the evolution of cooperation. © 2012 Springer-Verlag Berlin Heidelberg.


Lonsdorf E.V.,Franklin And Marshall College | Lonsdorf E.V.,Lester sher Center For The Study And Conservation Of Apes | Anderson K.E.,Lester sher Center For The Study And Conservation Of Apes | Stanton M.A.,George Washington University | And 5 more authors.
Animal Behaviour | Year: 2014

Sex differences in the behaviour of human children are a hotly debated and often controversial topic. However, several recent studies have documented a biological basis to key aspects of child social behaviour. To further explore the evolutionary basis of such differences, we investigated sex differences in sociability in wild chimpanzee, Pan troglodytes schweinfurthii, infants at Gombe National Park, Tanzania. We used a long-term data set on mother-infant behaviour to analyse the diversity of infant chimpanzee social partners from age 30 to 36 months. Male infants (N=12) interacted with significantly more individuals than female infants did (N=8), even when maternal sociability was controlled for. Furthermore, male infants interacted with significantly more adult males than female infants did. Our data indicate that the well-documented sex differences in adult chimpanzee social tendencies begin to appear quite early in development. Furthermore, these data suggest that the behavioural sex differences of human children are fundamentally rooted in our biological and evolutionary heritage. © 2013 The Association for the Study of Animal Behaviour.


Arcadi A.C.,Cornell University | Wallauer W.,The Jane Goodall Institute
International Journal of Primatology | Year: 2013

The role learning plays in the acquisition of communicative gestures by wild chimpanzees (Pan troglodytes) is unclear. We aimed to evaluate the likelihood that social experience influences the structure of chimpanzee buttress drumming displays by examining whether individuals differed in the way they used their hands and feet to strike trees. We analyzed digital video recordings of 245 bouts by 9 adult males from Gombe National Park, Tanzania, frame by frame in conjunction with acoustic analysis. We investigated 1) how limb sequences used to approach drumming trees influenced limb use during drumming, 2) the relative use of hands vs. feet in drumming, and 3) the relative amplitude of beats produced by hands vs. feet. We found that the chimpanzees most often approached trees at a gallop and usually initiated drumming bouts with limb sequences that were identical to gait limb sequences. All individuals produced more beats with their feet than with their hands, and foot beats were higher in relative amplitude than hand beats. In only one instance did an individual produce a bout with hands only, whereas in three of nine observations of drumming on resonant camp equipment, the individuals primarily used their hands rather than their feet. We suggest that although chimpanzees may, by observing others, learn to use buttresses as tools to generate loud sounds, it is unlikely that learning influences the structure of displays because they result from innately determined gait patterns deployed to generate sound from comparatively nonresonant substrates. © 2013 Springer Science+Business Media New York.


Jantz S.M.,University of Maryland University College | Pintea L.,The Jane Goodall Institute | Nackoney J.,University of Maryland University College | Hansen M.C.,University of Maryland University College
Remote Sensing | Year: 2016

All four chimpanzee sub-species populations are declining due to multiple factors including human-caused habitat loss. Effective conservation efforts are therefore needed to ensure their long-term survival. Habitat suitability models serve as useful tools for conservation planning by depicting relative environmental suitability in geographic space over time. Previous studies mapping chimpanzee habitat suitability have been limited to small regions or coarse spatial and temporal resolutions. Here, we used Random Forests regression to downscale a coarse resolution habitat suitability calibration dataset to estimate habitat suitability over the entire chimpanzee range at 30-m resolution. Our model predicted habitat suitability well with an r2 of 0.82 (±0.002) based on 50-fold cross validation where 75% of the data was used for model calibration and 25% for model testing; however, there was considerable variation in the predictive capability among the four sub-species modeled individually. We tested the influence of several variables derived from Landsat Enhanced Thematic Mapper Plus (ETM+) that included metrics of forest canopy and structure for four three-year time periods between 2000 and 2012. Elevation, Landsat ETM+ band 5 and Landsat derived canopy cover were the strongest predictors; highly suitable areas were associated with dense tree canopy cover for all but the Nigeria-Cameroon and Central Chimpanzee sub-species. Because the models were sensitive to such temporally based predictors, our results are the first to highlight the value of integrating continuously updated variables derived from satellite remote sensing into temporally dynamic habitat suitability models to support near real-time monitoring of habitat status and decision support systems. © 2016 by the authors.


PubMed | The Jane Goodall Institute, George Washington University, University of Minnesota and Duke University
Type: Journal Article | Journal: Behavioral ecology : official journal of the International Society for Behavioral Ecology | Year: 2016

The distribution and abundance of food resources are among the most important factors that influence animal behavioral strategies. Yet, spatial variation in feeding habitat quality is often difficult to assess with traditional methods that rely on extrapolation from plot survey data or remote sensing. Here, we show that maximum entropy species distribution modeling can be used to successfully predict small-scale variation in the distribution of 24 important plant food species for chimpanzees at Gombe National Park, Tanzania. We combined model predictions with behavioral observations to quantify feeding habitat quality as the cumulative dietary proportion of the species predicted to occur in a given location. This measure exhibited considerable spatial heterogeneity with elevation and latitude, both within and across main habitat types. We used model results to assess individual variation in habitat selection among adult chimpanzees during a 10-year period, testing predictions about trade-offs between foraging and reproductive effort. We found that nonswollen females selected the highest-quality habitats compared with swollen females or males, in line with predictions based on their energetic needs. Swollen females appeared to compromise feeding in favor of mating opportunities, suggesting that females rather than males change their ranging patterns in search of mates. Males generally occupied feeding habitats of lower quality, which may exacerbate energetic challenges of aggression and territory defense. Finally, we documented an increase in feeding habitat quality with community residence time in both sexes during the dry season, suggesting an influence of familiarity on foraging decisions in a highly heterogeneous landscape.


PubMed | University of Minnesota, The Jane Goodall Institute, Franklin And Marshall College, Emory University and Gombe Stream Research Center
Type: Journal Article | Journal: EcoHealth | Year: 2016

Recent advances in noninvasive detection methods for mycobacterial infection in primates create new opportunities for exploring the epidemiology of tuberculosis in free-living species. Chimpanzees (Pan troglodytes schweinfurthii) and baboons (Papio anubis) in Gombe National Park, Tanzania, were screened for infection with pathogens of the Mycobacterium tuberculosis Complex using Fecal IS6110 PCR; none was positive. This study demonstrates the feasibility of large-scale mycobacterial screening in wild primates.


Ihara Y.,University of Tokyo | Collins D.A.,The Jane Goodall Institute | Oda R.,Nagoya Institute of Technology | Matsumoto-Oda A.,University of Ryukyus
Behavioral Ecology and Sociobiology | Year: 2016

Abstract: Social structure of animal groups is affected by the spatial and temporal distribution of females. In particular, the extent to which fertile periods of females are temporally overlapped has been deemed as a crucial factor to determine the structure of social groups in primate species. Dominant males are less able to monopolize fertile females when there are more females being in estrous simultaneously. This provides a potential opportunity for females to manipulate their defensibility by dominant males by modifying the level of estrous overlap. Previous studies that have attempted to detect socially mediated synchrony or asynchrony of estrous cycles have produced mixed results, some of which have been questioned on methodological grounds. Here, we address this issue using an exceptionally large dataset of daily reproductive states in four troops of wild anubis baboons (Papio anubis) over 14 to 24 years (77 troop-years). We compare observed levels of estrous synchrony with null distributions obtained by a randomization procedure under the assumption that estrous cycles are mutually independent among females in the same troop. We do not find any evidence supporting synchrony or asynchrony of estrous cycles. Based on our result and those of previous studies in other species of baboons, we conclude that socially mediated synchrony or asynchrony is unlikely to play a significant role in structuring social groups in baboons. In addition, our analysis points out that care should be taken when applying randomization procedures to a dataset with missing observations. Significance statement: Females in some animal species have been suggested to synchronize or desynchronize their estrus cycles. This phenomenon may have a significant impact on the structure of animal societies because when there are more females simultaneously in estrus, even a dominant male is less able to defend them from other males. Previous attempts to detect non-random estrous cycles in primates have produced mixed results, and some of them have been criticized on the methodological grounds. We investigate whether wild female anubis baboons exhibit non-random estrous cycles using a larger dataset than previous studies. For a statistical analysis, we use a randomization procedure, taking a biasing effect of missing observations into consideration. Consistent with earlier studies on other species of baboons, our analysis does not find any evidence supporting estrous synchrony or asynchrony in anubis baboons. © 2016 Springer-Verlag Berlin Heidelberg


Gilby I.C.,Arizona State University | Machanda Z.P.,Harvard University | Mjungu D.C.,The Jane Goodall Institute | Rosen J.,Harvard University | And 3 more authors.
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2015

Even when hunting in groups is mutually beneficial, it is unclear howcommunal hunts are initiated. If it is costly to be the only hunter, individuals should be reluctant to hunt unless others already are. We used 70 years of data from three communities to examine how male chimpanzees ‘solve’ this apparent collective action problem. The ‘impact hunter’ hypothesis proposes that group hunts are sometimes catalysed by certain individuals that hunt more readily than others. In two communities (Kasekela and Kanyawara), we identified a total of five males that exhibited high hunt participation rates for their age, and whose presence at an encounter with red colobus monkeys increased group hunting probability. Critically, these impact hunters were observed to hunt first more often than expected by chance. We argue that by hunting first, these males dilute prey defences and create opportunities for previously reluctant participants. This by-product mutualism can explain variation in group hunting rates within and between social groups. Hunting rates declined after the death of impact hunter FG in Kasekela and after impact hunter MS stopped hunting frequently in Kanyawara. There were no impact hunters in the third, smaller community (Mitumba), where, unlike the others, hunting probability increased with the number of females present at an encounter with prey. © 2015 The Author(s) Published by the Royal Society. All rights reserved.


Grant
Agency: NSF | Branch: Standard Grant | Program: | Phase: FIELD STATIONS | Award Amount: 329.17K | Year: 2016

The Gombe Stream Research Centre (GSRC) was established in Tanzania by Dr. Jane Goodall in 1965 to support and maintain her pioneering study of chimpanzees, initiated in 1960. Now in its 56th year, the Gombe chimpanzee study is one of the longest and most detailed continuous studies of any free-living species. GSRC is a core project of the Jane Goodall Institute, one of the most well-known research and conservation organizations in the world. Research at GSRC has revealed the complex social behavior and cognitive abilities of chimpanzees including tool-making and use, group-hunting, cooperation in inter-group competition and enduring family bonds and social relationships, all of which have relevance to the understanding of human evolution. In addition, GSRC research informs community-centered conservation programs near Gombe and across Africa. Given the unparalleled depth of behavioral data, there has been growing interest from scientists in diverse fields in conducting broad, inter-disciplinary research at Gombe, to increase understanding of diet, physiology, health and disease. However, the GSRC infrastructure has been built piecemeal over the years and cannot support modern research or large trans-disciplinary teams. This project will extend and update the facilities by providing reliable power and renovating existing structures to provide state-of-the-art laboratory facilities for visiting scientists. Improvement of the facilities will improve current and future visiting researchers efficiency in all their research projects, and will enable the training of Tanzanian scientists and veterinarians through hands-on experience with indigenous species. A better power supply and improved internet connectivity will facilitate more immediate communication of scientific data and events at Gombe to collaborators and students overseas, as well as in local classrooms. A new library and museum space with power sources capable of supporting video displays will greatly improve the educational experiences of visiting students, school groups, and tourists.

The provision of modern lab facilities at this iconic site will enable transformative research through coupling the exceptionally deep knowledge of the primates and the habitat with new techniques to detect and measure disease agents and disease progression in situ, endocrine levels, characteristics of bone, and nutritional and isotopic characteristics of dietary items. Improved power and communication will support all ongoing research projects and allow for greater synergy between them. The expansion and renovation will feature 1) reliable electrical power through new solar and backup generator systems, 2) wet laboratory space equipped with freezers for sample storage and basic equipment for genetic, endocrine, and nutritional analysis, 3) dry storage and work space for an herbarium and for the uniquely extensive skeletal collections of individual chimpanzees and baboons of known developmental and life histories, 4) a necropsy lab, 5) a space for meetings, and 6) a small museum. Information on the core research projects conducted at Gombe can be found at www.gombechimpanzees.org.

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