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The expansion of agriculture in equatorial areas is fragmenting and reducing wildlife habitats. For primates, it also increases opportunities to consume crops as high-energy resources, exacerbates conflicts with farmers, and increases exposure to diseases and agrochemicals at the edge of protected areas. In species with sex differences in ranging behavior, individual exposure to such opportunities and threats may vary by sex. Chimpanzees show a great feeding flexibility and are territorial species with varied ranging patterns according to site, sex, or individuals. Within a community whose territory is crossed by a high-traffic road and partially bordered by maize gardens, we tested hypotheses of interindividual differences in access to crops based on age, sex, ranging behavior, and kinship. By analyzing the presence of Sebitoli chimpanzees (Pan troglodytes schweinfurthii , Kibale National Park, Uganda) on video clips from 16 camera traps, we estimated the individual dispersion range across the community's territory and the crop foraging frequency along maize gardens over 16 months. While all age and sex classes were represented at the forest–garden interface, large intrasex differences were observed: some mature males and females were not observed to participate. The crop foraging frequency of adult females in maize gardens was significantly correlated with the location of their ranging areas. Related individuals revealed similar range patterns within the forest territory without sharing crop foraging habits. However, social learning and energy and risks–benefits trade-offs as potential drivers of crop consumption are not excluded. [ABSTRACT FROM AUTHOR]

Variance in the quality of food sites exploited by group-living animals should allow dominant individuals to gain feeding advantages. In some cases of eating in large patches, however, the amount of agonism can be puzzlingly low. We studied this problem in wild adult chimpanzees, Pan troglodytes , eating ripe fruits in large tree crowns, a context in which little aggression has previously been recorded. Observations were conducted from within the same tree crown as feeding chimpanzees, which allowed us to obtain high-quality data on food distribution, feeding behaviour and aggression. We assessed energy availability and chimpanzee behaviour in relation to their feeding depth. Deeper food sites were associated with less metabolizable food energy (kcal/m3) and lower energy intake rates (kcal/min). Energy availability also varied by tree type (higher in drupe trees than in fig trees) and fruit ripeness (higher in riper fruits). Males were dominant to females, and within both sexes aggressive interactions conformed to a linear hierarchy. Overall higher-ranking individuals used aggression and dominance to access superior feeding sites and achieve higher rates of energy intake, but the effects of dominance varied according to tree type, sex and party composition. Our study shows that covert contest competition over feeding sites gave dominant individuals an important advantage even in very large patches. • Within fruit trees, higher food sites produced more metabolizable energy. • Higher food sites were controlled by higher-ranking males and females. • In single-sex parties, females competed for food sites, but males did not. • In mixed-sex parties, female and male feeding success varied with social rank. • Between-female variation in feeding success was reduced in the presence of males. [ABSTRACT FROM AUTHOR]

Objectives: Sodium, a vital micronutrient that is often in scarce supply for tropical herbivores, is sometimes found at high concentration in decaying wood. We tested two hypotheses for chimpanzees: first, that wood‐eating facilitates acquisition of sodium; second, that wood‐eating occurs in response to the low availability of sodium from other dietary sources. Materials and Methods: We studied the behavior of more than 50 chimpanzees of all age‐sex classes in the Kanyawara community of Kibale National Park, Uganda. We quantified the sodium content of dietary items, including wood samples from tree species that chimpanzees consumed or did not consume. To assess variation in sodium intake, we used 7 years of data on time spent feeding on plant foods, 18 months of data on rates of food intake by adult females, and 20 years of data on meat‐eating. Results: Major dietary sources of sodium were wood, fruits and meat. Chimpanzees consumed wood primarily from decaying trees of Neoboutonia macrocalyx (Euphorbiaceae), which had substantially higher sodium content than all other dietary items tested. Wood‐eating was negatively correlated with fruit‐eating. Females ate wood more often than males, while males had a greater probability of consuming meat at predation events. Discussion We propose that females ate wood more often than males because females had reduced access to meat, their preferred source of sodium. This hypothesis suggests that the need for sodium is a motivating reason for chimpanzees to consume both meat and wood. [ABSTRACT FROM AUTHOR]

Stable isotope values in primate tissues can be used to reconstruct diet in the absence of direct observation. However, in order to make dietary inferences, one must first establish isotopic variability for potential food sources. In this study we examine stable carbon isotope (δ13C) values for chimpanzee ( Pan troglodytes) food resources from two Ugandan forests: Ngogo (Kibale National Park), and Bwindi Impenetrable National Park. Mean δ13C values for plant samples are equivalent at both sites. Plant δ13C values are best explained by a multivariate linear model including plant part (leaves, pith, flowers, and fruit), vertical position within the canopy (canopy vs. ground), and taxon ( R2 = 0.6992). At both sites, leaves had the lowest δ13C values followed by pith and fruit. Canopy resources have comparable δ13C values at the two sites but ground resources have lower δ13C values at Ngogo than Bwindi (−30.7 vs. −28.6‰). Consequently, isotopic differences between ground and canopy resources (4.2 vs. 2.2‰), and among plant parts are more pronounced at Ngogo. These results demonstrate that underlying environmental differences between sites can produce variable δ13C signatures among primate food resources. In the absence of observation data or isotope values for local vegetation, caution must be taken when interpreting isotopic differences among geographically or temporally separated populations or species. Am. J. Primatol. 78:1031-1040, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Despite the spread of road infrastructures throughout Africa to support regional development, industry, and tourism, few studies have examined how wild animals adapt their behavior and ecology in road-forest ecotones. Indeed, while numerous studies have demonstrated chimpanzee adaptability in anthropogenic landscapes, none have examined the effects of asphalted highways on wild chimpanzee behaviors. In a 29-month survey, we assessed the dangers posed by an asphalted road crossing the Sebitoli area of Kibale National Park (Uganda). We analyzed 122 individual chimpanzee crossings. Although the asphalted road represents a substantial threat to crossing animals (89 motorized vehicles per hour use this road and individuals of six different primate species were killed in 1 year), chimpanzees took into account this risk. More than 90% of the individuals looked right and left before and while crossing. Chimpanzees crossed in small subgroups (average 2.7 subgroups of 2.1 individuals per crossing event). Whole parties crossed more rapidly when chimpanzees were more numerous in the crossing groups. The individuals most vulnerable to the dangers of road crossing (females with dependents, immature, and severely injured individuals) crossed less frequently compared with non-vulnerable individuals (lone and healthy adolescents and adults). Moreover, healthy adult males, who were the most frequent crossing individuals, led progressions more frequently when crossing the road than when climbing or descending feeding trees. Almost 20% of the individuals that crossed paid attention to conspecifics by checking on them or waiting for them while crossing. These observations are relevant for our understanding of adaptive behavior among chimpanzees in human-impacted habitats. Further investigations are needed to better evaluate the effects of busy roads on adolescent female dispersal and on their use of territories. Mitigation measures (e.g., bridges, underpasses, reduced speed limits, speed-bumps, signposts, or police controls) should be established in this area. Am. J. Primatol. 77:890-900, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Anthropogenic disturbances present challenges to animals. Behavioural plasticity is one way that animals adjust to degraded habitats. In the present study, we examined how ecological conditions impact reproduction of female red colobus monkeys, Procolobus rufomitratus, in Kibale National Park, Uganda. Wrangham (2002, Behavioural diversity in chimpanzees and bonobos, pp. 204–215) proposed the ‘cost of sexual attraction’ hypothesis to explain the relationship between ecology and female reproduction. Here for the first time we test and expand on this hypothesis in a folivorous species, the red colobus monkey. We compared four groups of red colobus, two in previously logged areas and two in old-growth areas, to examine differences in female reproductive behaviours and physiologies. We predicted that, because of differences in food availability, females living in logged areas would (1) have a shorter duration of genital tumescence, (2) mate less frequently and (3) constrain mating behaviours more to periods of maximal genital tumescence compared to females in old-growth areas. As predicted, females in logged areas were fully tumescent for a significantly shorter period, copulated significantly less frequently and showed mating behaviours when fully inflated significantly more than females in old-growth areas. This behavioural plasticity contributes to the maintenance of female reproductive function in the face of environmental constraints associated with anthropogenic disturbance that influences food resources. [ABSTRACT FROM AUTHOR]

Background: Malaria parasites (Plasmodium sp.), including new species, have recently been discovered as low grade mixed infections in three wild chimpanzees (Pan troglodytes schweinfurthii) sampled randomly in Kibale National Park, Uganda. This suggested a high prevalence of malaria infection in this community. The clinical course of malaria in chimpanzees and the species of the vectors that transmit their parasites are not known. The fact that these apes display a specific behaviour in which they consume plant parts of low nutritional value but that contain compounds with anti-malarial properties suggests that the apes' health might be affected by the parasite. The avoidance of the night-biting anopheline mosquitoes is another potential behavioural adaptation that would lead to a decrease in the number of infectious bites and consequently malaria. Methods: Mosquitoes were collected over two years using suction-light traps and yeast-generated CO2 traps at the nesting and the feeding sites of two chimpanzee communities in Kibale National Park. The species of the female Anopheles caught were then determined and the presence of Plasmodium was sought in these insects by PCR amplification. Results: The mosquito catches yielded a total of 309 female Anopheles specimens, the only known vectors of malaria parasites of mammalians. These specimens belonged to 10 species, of which Anopheles implexus, Anopheles vinckei and Anopheles demeilloni dominated. Sensitive DNA amplification techniques failed to detect any Plasmodium-positive Anopheles specimens. Humidity and trap height influenced the Anopheles capture success, and there was a negative correlation between nest numbers and mosquito abundance. The anopheline mosquitoes were also less diverse and numerous in sites where chimpanzees were nesting as compared to those where they were feeding. Conclusions: These observations suggest that the sites where chimpanzees build their nests every night might be selected, at least in part, in order to minimize contact with anopheline mosquitoes, which might lead to a reduced risk in acquiring malaria infections. [ABSTRACT FROM AUTHOR]

Chimpanzees are well known for their territorial behavior. Males who belong to the same community routinely patrol their territories, occasionally making deep incursions into those of their neighbors. Male chimpanzees may obtain several fitness benefits by participating in territorial boundary patrols, but patrolling is also likely to involve fitness costs. Patrollers risk injury or even death, and patrols may be energetically costly and may involve opportunity costs. Although territorial patrols have been reported at all long-term chimpanzee study sites, quantitative data on their energetic costs have not previously been available. I evaluated the energy costs of patrolling for male chimpanzees at Ngogo, Kibale National Park, Uganda during 14 months of observation. In 29 patrols and matched control periods, I recorded the distances covered and time spent traveling and feeding by chimpanzees. I found that male chimpanzees covered longer distances, spent more time traveling, and spent less time feeding during patrols than during control periods. These results support the hypothesis that chimpanzees incur energetic costs while patrolling and suggest that ecological factors may constrain the ability of chimpanzees to patrol. Am. J. Primatol. 72:93–103, 2010. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Using the line transect methods, I studied the primate density at Ngogo, Kibale National Park, Uganda for 18 months. Comparisons with other studies show that the population of red colobus monkeys (Procolobus rufomitratus) and blue monkeys (Cercopithecus mitis) is declining, whereas the populations of black-and-white colobus (Colobus guereza), red-tailed monkeys (Cercopithecus ascanius), grey-cheeked mangabeys (Lophocebus albigena), baboons (Papio anubis), and chimpanzees (Pan troglodytes) remain constant or slightly increase. In this paper, I compare data on density from this study to data from previous and recent censuses at Ngogo and with data from other sites in the Kibale forest to examine the stability of primate populations. Furthermore, I test the hypothesis that the changes in red colobus and blue monkey density are due to changes in the forest structure and abundance of their most selected feeding trees, and show that changes in forest composition cannot account for changes in their red colobus abundance, but that hunting by chimpanzees provides a reasonable explanation. Am. J. Primatol. 69:1030–1044, 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Colobines often associate with cercopithecines at various African sites. Such polyspecific associations presumably have an antipredation function. At Ngogo, Kibale National Park, Uganda, red colobus ( Procolobus rufomitratus) spend considerable time in association with red-tailed monkeys ( Cercopithecus ascanius), and they are also heavily hunted by chimpanzees ( Pan troglodytes). I conducted behavioral observations and playback experiments to test the hypothesis that red colobus and red-tailed monkeys obtain mutual protection and predator-related benefits by associating. Despite high chimpanzee hunting pressure on red colobus and much lower hunting pressure on red-tailed monkeys, red-tailed monkeys initiate, maintain, and terminate the associations. The results suggest that rather than providing red colobus with protection against chimpanzees, the associations occur mostly because they protect red-tailed monkeys against predation by eagles. [ABSTRACT FROM AUTHOR]

Kibale National Park (KNP), Uganda, has a number of chimpanzees habituated for tourism. The close genetic relationship between humans and chimpanzees means that there is the potential for disease transmission between the two. The aim of this study was to establish the diseases to which chimpanzees may be exposed by surveying the medical histories of humans in contact with the chimpanzees of KNP. Medical questionnaires were given to tourists visiting KNP and to the population of a village close to the park. The 62 tourist surveys returned indicated a high prevalence of disease symptoms, in particular diarrhoea, as well as ongoing infectious diseases and a lack of current vaccinations. The 50 local surveys returned also indicated a high prevalence of disease symptoms, in particular respiratory disease, along with a low rate of vaccination and a high frequency of visual contact with the chimpanzees both within and outside KNP. This study indicates that humans are a potential source of infection for chimpanzees. The results, which have been communicated to the appropriate authorities, will assist in the devising of proper tourist viewing regulations and provide local health authorities with the information necessary to improve both public health and chimpanzee health. Further recommendations include education of tourists regarding appropriate vaccinations, hand washing prior to the visit, the use of facemasks during the visit, and the provision of latrines. Chimpanzee ecotourism is becoming increasingly popular and protecting the chimpanzees’ health will help to ensure that ecotourism is a sustainable activity. [ABSTRACT FROM AUTHOR]

The attitudes of community members living around protected areas are an important and often overlooked consideration for effective conservation strategies. Around Kibale National Park (KNP) in western Uganda, communities regularly face the threat of crop destruction from wildlife, including from a variety of endangered species, such as African elephants (Loxodonta africana), common chimpanzees (Pan troglodytes), and red colobus monkeys (Piliocolobus tephrosceles), as well as other nonhuman primates, including olive baboons (Papio anubis). These frequent negative interactions with wildlife lead many community members to resent the park and the animals that live within it. To mitigate these issues, community members around KNP partnered with researchers to start a participatory action research project to reduce human-wildlife interactions. The project tested four sustainable human-wildlife conflict mitigation strategies: digging and maintaining trenches around the park border, installing beehive fences in swampy areas where trenches could not be dug, planting tea as a buffer, and growing garlic as a cash crop. These physical exclusion methods and agriculture-based deterrents aimed to reduce crop destruction by wild animals and improve conditions for humans and wildlife alike. We conducted oral surveys with members of participating communities and a nonparticipating community that border KNP to determine the impact of these sustainable human-wildlife conflict mitigation strategies on attitudes toward KNP, wildlife officials, and animal species in and around KNP. We found that there is a positive correlation between participation in the project and perceived benefits of living near KNP. We also found that respondents who participated in the project reported more positive feelings about the Uganda Wildlife Authority, the organization that oversees KNP. This research will help inform future conservation initiatives around KNP and other areas where humans and animals face conflict through crop damage. [ABSTRACT FROM AUTHOR]