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The nearly universal right hand preference manifested by human populations is one of the most pronounced manifestations of population-level lateralization. Morphological and archeological evidence indicate that this behavioral specialization may have emerged among our hominin ancestors. Whether population-level behavioral asymmetries are evident in non-human animals remains a topic of considerable scientific debate, with the most consistent evidence of population-level trends emerging from studies of chimpanzees ( Pan troglodytes). However, previous studies of population-level lateralization in wild apes have relied upon data sets pooled across populations to reach adequate sample sizes. Our aim was to test for population-level handedness within a single wild chimpanzee population, and also to determine if performance asymmetries were associated with handedness. To address these questions, we coded handedness and duration of fishing probe insertions from remote video footage of chimpanzee visitation to termite nests (totaling 119 hr) in the Goualougo Triangle, Republic of Congo. Similar to reports from other populations, chimpanzees in the Goualougo Triangle showed robust individual hand preferences for termite fishing. There were 46 right-handed, 39 left-handed, and 4 ambiguously-handed individuals. Though we did not detect an overall significant population-level handedness ( t(88) = 0.83, n.s.) in this study, males showed a greater right hand preference than females. Further, we found that average dipping latencies were significantly faster for right- compared to left-handed chimpanzees. Possible explanations and evolutionary implications of taxa- and task-specific patterns of population-level laterality are discussed. Am. J. Primatol. 78:1190-1200, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT Studies of chimpanzee termite foraging enlighten our understanding of early hominin tool use not only by modeling the cognitive ability of our ancestors but also by emphasizing the possible role of social insects in the hominin diet. The chimpanzees of the Goualougo Triangle are known to have one of the largest and most complex tool repertoires reported for wild chimpanzees. One tool set habitually used by this population includes a perforating tool to penetrate the hard outer crust of elevated termite nests before fishing for termite prey with an herbaceous stem. Here, we report the variation present in the grips used on the perforating tool. Our analysis of video recordings of chimpanzee visitation to termite nests over a 3-year period shows that these chimpanzees use a variety of grips to navigate the challenges encountered in opening a termite nest. For situations in which the soil is most hardened, perforating requires force and a power grip is often used. When the soil in the passageway is loose, precision grips are suitable for the task. One of the preferred grips reported here is an interdigital brace, which has previously been described in studies of how some people hold a pencil. In this study, for the first time, the interdigital brace has been thoroughly described for chimpanzees. The various strategies and grips used during perforation emphasize the importance of termites as a nutritional resource that should be considered more strongly as a food used by early hominins. Am J Phys Anthropol 157:252-259, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

The emergence of technology has been suggested to coincide with scarcity of staple resources that led to innovations in the form of tool-assisted strategies to diversify or augment typical diets. We examined seasonal patterns of several types of tool use exhibited by a chimpanzee (Pan troglodytes) population residing in central Africa, to determine whether their technical skills provided access to fallback resources when preferred food items were scarce. Chimpanzees in the Goualougo Triangle exhibit a diverse repertoire of tool behaviours, many of which are exhibited throughout the year. Further, they have developed specific tool sets to overcome the issues of accessibility to particular food items. Our conclusion is that these chimpanzees use a sophisticated tool technology to cope with seasonal changes in relative food abundance and gain access to high-quality foods. Subgroup sizes were smaller in tool using contexts than other foraging contexts, suggesting that the size of the social group may not be as important in promoting complex tool traditions as the frequency and type of social interactions. Further, reports from other populations and species showed that tool use may occur more often in response to ecological opportunities and relative profitability of foraging techniques than scarcity of resources. [ABSTRACT FROM AUTHOR]

Several populations of chimpanzees have been reported to prey upon Dorylus army ants. The most common tool-using technique to gather these ants is with “dipping” probes, which vary in length with regard to aggressiveness and lifestyle of the prey species. We report the use of a tool set in army ant predation by chimpanzees in the Goualougo Triangle, Republic of Congo. We recovered 1,060 tools used in this context and collected 25 video recordings of chimpanzee tool-using behavior at ant nests. Two different types of tools were distinguished based on their form and function. The chimpanzees use a woody sapling to perforate the ant nest, and then a herb stem as a dipping tool to harvest the ants. All of the species of ants preyed upon in Goualougo are present and consumed by chimpanzees at other sites, but there are no other reports of such a regular or widespread use of more than one type of tool to prey upon Dorylus ants. Furthermore, this tool set differs from other types of tool combinations used by chimpanzees at this site for preying upon termites or gathering honey. Therefore, we conclude that these chimpanzees have developed a specialized method for preying upon army ants, which involves the use of an additional tool for opening nests. Further research is needed to determine which specific ecological and social factors may have shaped the emergence and maintenance of this technology. Am. J. Primatol. 72:17–24, 2010. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Several populations of wild chimpanzees use tools to raid bee nests, but preliminary observations of chimpanzees in the Congo Basin indicate that they may have developed sophisticated technical solutions to gather honey that differ from those of apes in other regions. Despite the lack of habituated groups within the range of the central subspecies, there have been several reports of different types of tools used by chimpanzees to open beehives and gather honey. Researchers have observed some of these behaviors (honey dipping) in populations of western and eastern chimpanzees, whereas others (hive pounding) may be limited to this region. Toward evaluating hypotheses of regional tool using patterns, we provide the first repeated direct observations and systematic documentation of tool use in honey-gathering by a population of Pan troglodytes troglodytes. Between 2002 and 2006, we observed 40 episodes of tool use in honey-gathering by chimpanzees in the Goualougo Triangle, Republic of Congo. Pounding was the most common and successful strategy to open beehives. Chimpanzees at this site used several tools in a single tool-using episode and could also attribute multiple functions to a single tool. They exhibited flexibility in responses toward progress in opening a hive and hierarchical structuring of tool sequences. Our results support suggestions of regional tool using traditions in honey-gathering, which could be shaped by variation in bee ecology across the chimpanzee range. Further, we suggest that these chimpanzees may have an enhanced propensity to use tool sets that could be related to other aspects of their tool repertoire. Clearly, there is still much to be learned about the behavioral diversity of chimpanzees residing within the Congo Basin. [ABSTRACT FROM AUTHOR]

Abstract: With the exception of humans, chimpanzees show the most diverse and complex tool-using repertoires of all extant species. Specific tool repertoires differ between wild chimpanzee populations, but no apparent genetic or environmental factors have emerged as definitive forces shaping variation between populations. However, identification of such patterns has likely been hindered by a lack of information from chimpanzee taxa residing in central Africa. We report our observations of the technological system of chimpanzees in the Goualougo Triangle, located in the Republic of Congo, which is the first study to compile a complete tool repertoire from the Lower Guinean subspecies of chimpanzee (Pan troglodytes troglodytes). Between 1999 and 2006, we documented the tool use of chimpanzees by direct observations, remote video monitoring, and collections of tool assemblages. We observed 22 different types of tool behavior, almost half of which were habitual (shown repeatedly by several individuals) or customary (shown by most members of at least one age-sex class). Several behaviors considered universals among chimpanzees were confirmed in this population, but we also report the first observations of known individuals using tools to perforate termite nests, puncture termite nests, pound for honey, and use leafy twigs for rain cover. Tool behavior in this chimpanzee population ranged from simple tasks to hierarchical sequences. We report three different tool sets and a high degree of tool-material selectivity for particular tasks, which are otherwise rare in wild chimpanzees. Chimpanzees in the Goualougo Triangle are shown to have one of the largest and most complex tool repertoires reported in wild chimpanzee populations. We highlight new insights from this chimpanzee population to our understanding of ape technological systems and evolutionary models of tool-using behavior. [Copyright &y& Elsevier]

Reports describing the implementation of innovative facility designs are important to both the primate caregiving community and policymakers reviewing current U.S. Department of Agriculture regulations. This study documents the changes in behavior of 5 adult chimpanzees that coincided with transfer from the Psychology Building Facility to the large and complex chimpanzee enclosure within the Chimpanzee and Human Communication Institute (CHCI) in Ellensburg, Washington. In 1993, the chimpanzees were relocated from a small facility with a 27.87-m[sup 2] indoor suite of enclosures to a new 587-m[sup 2] indoor and outdoor facility. The 1st study compares the activity budgets of the chimpanzees before and after the transfer. The 2nd study compares patterns of locomotion at the 2 facilities. The 3rd study examines the chimpanzees' patterns of use of the features at the new facility. The chimpanzees traveled more and exhibited more species-typical behaviors at the CHCI, including climbing and leaping. The pattern of locomotion and postures at the CHCI was similar to the pattern of locomotion and postures observed in free-ranging chimpanzee populations. The chimpanzees used all structures and all areas in the facility, especially elevated structures and the outdoor enclosure. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Globally, the conservation value of big trees is linked to biodiversity and carbon sequestration. We studied trees, greater than 80 cm in diameter, in a forest in the Republic of Congo. We found that more than 100 species reach this size and the most abundant species is Sapele (Entandrophragma cylindricum), which is exploited for global timber markets. More than 40% of the large tree species are used by local people for food. Our results show that big trees are important to local people in the Congo Basin in addition to being the focus of industrial logging and in many areas the basis for the formal economy. Summary: The main aim of this paper is to establish standard techniques for surveying the biggest trees in tropical rain forests.One hundred and thirty hectares (13 plots of 10 ha) of unlogged mixed species terra firma forest in the Republic of Congo were surveyed for trees greater than 80 cm in diameter.More than 100 species of tree exceed 80 cm in diameter and one species, Entandrophragma cylindricum (Sapele or Sapelli), dominates this size class.Obtaining comparable data of big trees from different sites across the tropics is a priority. We propose a standardised plot size of 10 ha, replicated 10 times for each forest type at different study sites and a minimum trunk diameter of 70 cm at breast height or above buttresses. [ABSTRACT FROM AUTHOR]

ABSTRACT: Nonhuman primate appearance and behavior can be better understood through documentary footage than through verbal explanation alone. Many college instructors show primate documentary films in their courses, but little research has evaluated primate documentaries as teaching tools. We sought to determine the prevalence of documentary use in teaching and which characteristics of documentaries affect their use. An online survey queried 219 college‐level anthropology instructors about their use and perceptions of primate documentary films. Most instructors (96.3 percent) showed documentaries in the classroom, incorporating new documentaries when available. Several multispecies documentaries were widely used. Documentaries rated high in usefulness for teaching purposes were seen as more entertaining and accurate, and as less anthropomorphic and misleading, with usefulness unrelated to perceptions that films were conservation oriented. Documentary selection was driven by teaching usefulness, availability, and the number of species in the film. In addition, we created the Primate Films Database, a comprehensive database of primate documentary films with reviews, runtimes, featured‐species identifications, and teaching‐usefulness ratings provided both by our participants and us. It is a publicly available online resource designed to raise awareness of primate documentary films as educational tools and to facilitate more widespread use of high‐quality multimedia resources in anthropology classrooms. [biological anthropology, documentary film, primates, visual anthropology] [ABSTRACT FROM AUTHOR]

Chimpanzees (Pan troglodytes) harbor rich assemblages of malaria parasites, including three species closely related to P. falciparum (sub-genus Laverania), the most malignant human malaria parasite. Here, we characterize the ecology and epidemiology of malaria infection in wild chimpanzee reservoirs. We used molecular assays to screen chimpanzee fecal samples, collected longitudinally and cross-sectionally from wild populations, for malaria parasite mitochondrial DNA. We found that chimpanzee malaria parasitism has an early age of onset and varies seasonally in prevalence. A subset of samples revealed Hepatocystis mitochondrial DNA, with phylogenetic analyses suggesting that Hepatocystis appears to cross species barriers more easily than Laverania. Longitudinal and cross-sectional sampling independently support the hypothesis that mean ambient temperature drives spatiotemporal variation in chimpanzee Laverania infection. Infection probability peaked at ~24.5 °C, consistent with the empirical transmission optimum of P. falciparum in humans. Forest cover was also positively correlated with spatial variation in Laverania prevalence, consistent with the observation that forest-dwelling Anophelines are the primary vectors. Extrapolating these relationships across equatorial Africa, we map spatiotemporal variation in the suitability of chimpanzee habitat for Laverania transmission, offering a hypothetical baseline indicator of human exposure risk. Chimpanzees are known to suffer from malaria parasitism. Here, the prevalence and epidemiology of several malaria parasites is examined in a wild chimpanzee population. [ABSTRACT FROM AUTHOR]

Although the phenomenon of termite fishing by chimpanzees (Pan troglodytes) has historical and theoretical importance for primatology, we still have a limited understanding of how chimpanzees accomplish this activity, and in particular, about details of skilled actions and the nature of individual variation in fishing techniques. We examined movements, hand positions, grips, and other details from remote video footage of seven adult and subadult female chimpanzees using plant probes to extract Macrotermes muelleri termites from epigeal nests. Six chimpanzees used exclusively one hand (left or right) to grip the probe during termite fishing. All chimpanzees used the same repertoire of actions to insert, adjust, and withdraw the probe but differed in the frequency of use of particular actions. Chimpanzees have been described as eating termites in two ways—directly from the probe or by sweeping them from the probe with one hand. We describe a third technique: sliding the probe between the digits of one stationary hand as the probe is extracted from the nest. The sliding technique requires complementary bimanual coordination (extracting with one hand and grasping lightly with the other, at the same time). We highlight the importance of actions with two hands—one gripping, one assisting—in termite fishing and discuss how probing techniques are correlated with performance. Additional research on digital function and on environmental, organismic, and task constraints will further reveal manual dexterity in termite fishing. Research Highlights: ‐Using remote video footage from camera traps in Goualougo Triangle, Republic of Congo, we describe chimpanzees' manual actions, postures, and positions, and movements of the probe while they fished for termites in epigeal termite nests.‐Chimpanzees used diverse grips, with and without the thumb, and two hands—one gripping, one assisting—to handle the probe delicately and to move it precisely.‐We describe a new technique for recovering termites: sliding the probe between the digits of one stationary hand as the probe is extracted from the nest with the other hand, and a new action: oscillatory movements of the probe while it was inserted in the nest. [ABSTRACT FROM AUTHOR]

Documentary films are intended to engage a broad audience and can be effective outreach tools for raising awareness of global biodiversity and conservation issues. We screened 210 films and recorded the duration that each primate species was on screen to evaluate their representation in documentaries and to assess factors potentially driving biases within these depictions. We expected that flagship species would be overrepresented such that: 1) apes would be more frequently included in documentaries than other primate taxa, 2) Critically Endangered and Endangered species would be more frequently included in documentaries than those of less concern, and 3) large-bodied primates would have more on-screen time than smaller-bodied primates. Due to factors affecting the accessibility of species, we hypothesized that: 4) species of Least Concern would be overrepresented, and 5) diurnal and cathemeral primates would be overrepresented compared to nocturnal primates. We found that documentary films portray only a fraction of primate biodiversity. Only a third of primate species are portrayed in documentaries, and these tend to be large flagship species and easily filmed species. African apes were overrepresented compared to other primate taxa. Endangered and Least Concern species were overrepresented, whereas Vulnerable and Near Threatened species were underrepresented. Larger-bodied species and non-nocturnal primates were featured in more films and had longer on-screen times than smaller or nocturnal primates. Our findings suggest that audiences may benefit from the collaboration of filmmakers and scientists, which would likely result in greater species representation and more comprehensive coverage of relevant conservation issues. • Less than one third of known primate species appear in primate documentaries. • Large-bodied diurnal primates are disproportionately represented in documentaries. • Underrepresenting biodiversity in documentaries may have conservation implications. • Filmmakers and scientists should work together for better species representation. [ABSTRACT FROM AUTHOR]

The Laverania clade comprises the human malaria parasite Plasmodium falciparum as well as at least seven additional parasite species that infect wild African apes. A recent analysis of Laverania genome sequences (Otto TD, et al. 2018. Genomes of all known members of a Plasmodium subgenus reveal paths to virulent human malaria. Nat Microbiol. 3: 687–697) reported three instances of interspecies gene transfer, one of which had previously been described. Generating gene sequences from additional ape parasites and re-examining sequencing reads generated in the Otto et al. study, we identified one of the newly described gene transfers as an assembly artifact of sequences derived from a sample coinfected by two parasite species. The second gene transfer between ancestors of two divergent chimpanzee parasite lineages was confirmed, but involved a much larger number of genes than originally described, many of which encode exported proteins that remodel, or bind to, erythrocytes. Because successful hybridization between Laverania species is very rare, it will be important to determine to what extent these gene transfers have shaped their host interactions. [ABSTRACT FROM AUTHOR]

In 2006–2007 we observed an unusual mortality event among apes in northern Republic of Congo that, although not diagnostically confirmed, we believe to have been a disease outbreak. In 2007–2011 we conducted ape nest surveys in the region, recording 11,835 G. g. gorilla nests (2,262 groups) and 5,548 P. t. troglodytes nests (2,139 groups). We developed a statistical model to determine likely points of origin of the outbreak to help identify variables associated with disease emergence and spread. We modeled disease spread across the study area, using suitable habitat conditions for apes as proxy for local ape densities. Infectious status outputs from that spread model were then used alongside vegetation, temperature, precipitation and human impact factors as explanatory variables in a Generalized Linear Model framework to explain observed 2007–2011 ape nest trends in the region. The best models predicted emergence in the western region of Odzala-Kokoua National Park and north of the last confirmed Ebola virus disease epizootics. Roads were consistently associated with attenuation of modeled virus spread. As disease is amongst the leading threats to great apes, gaining a better understanding of disease transmission dynamics in these species is imperative. Identifying ecological drivers underpinning a disease emergence event and transmission dynamics in apes is critical to creating better predictive models to guide wildlife management, develop potential protective measures for wildlife and to reduce potential zoonotic transmission to humans. The results of our model represent an important step in understanding variables related to great ape disease ecology in Central Africa. [ABSTRACT FROM AUTHOR]

Plasmodium falciparum is the most prevalent and lethal of the malaria parasites infecting humans, yet the origin and evolutionary history of this important pathogen remain controversial. Here we develop a single-genome amplification strategy to identify and characterize Plasmodium spp. DNA sequences in faecal samples from wild-living apes. Among nearly 3,000 specimens collected from field sites throughout central Africa, we found Plasmodium infection in chimpanzees (Pan troglodytes) and western gorillas (Gorilla gorilla), but not in eastern gorillas (Gorilla beringei) or bonobos (Pan paniscus). Ape plasmodial infections were highly prevalent, widely distributed and almost always made up of mixed parasite species. Analysis of more than 1,100 mitochondrial, apicoplast and nuclear gene sequences from chimpanzees and gorillas revealed that 99% grouped within one of six host-specific lineages representing distinct Plasmodium species within the subgenus Laverania. One of these from western gorillas comprised parasites that were nearly identical to P. falciparum. In phylogenetic analyses of full-length mitochondrial sequences, human P. falciparum formed a monophyletic lineage within the gorilla parasite radiation. These findings indicate that P. falciparum is of gorilla origin and not of chimpanzee, bonobo or ancient human origin. [ABSTRACT FROM AUTHOR]

Practical and ethical constraints limit our ability to experimentally test socioecological theory in wild primates. We took an alternate approach to model this, allowing groups of humans to interact in a virtual world in which they had to find food and interact with both ingroup and outgroup avatars to earn rewards. We altered ratios and distributions of high- and low-value foods to test the hypothesis that hominoids vary with regards to social cohesion and intergroup tolerance due to their feeding ecology. We found larger nesting clusters and decreased attacks on outgroup competitors in the Bonobo condition versus the Chimpanzee condition, suggesting a significant effect of feeding competition alone on social structure. We also demonstrate that virtual worlds are a robust mechanism for testing hypotheses that are impossible to study in the wild. [ABSTRACT FROM AUTHOR]

Chimpanzees and gorillas are the only nonhuman primates known to harbor viruses closely related to HIV-1. Phylogenetic analyses showed that gorillas acquired the simian immunodeficiency virus SIVgor from chimpanzees, and viruses from the SIVcpz/SIVgor lineage have been transmitted to humans on at least four occasions, leading to HIV-1 groups M, N, O, and P. To determine the geographic distribution, prevalence, and species association of SIVgor, we conducted a comprehensive molecular epidemiological survey of wild gorillas in Central Africa. Gorilla fecal samples were collected in the range of western lowland gorillas (n = 2,367) and eastern Grauer gorillas (n = 183) and tested for SIVgor antibodies and nucleic acids. SIVgor antibody-positive samples were identified at 2 sites in Cameroon, with no evidence of infection at 19 other sites, including 3 in the range of the Eastern gorillas. In Cameroon, based on DNA and microsatellite analyses of a subset of samples, we estimated the prevalence of SIVgor to be 1.6% (range, 0% to 4.6%), which is significantly lower than the prevalence of SIVcpzPtt in chimpanzees (5.9%; range, 0% to 32%). All newly identified SIVgor strains formed a monophyletic lineage within the SIVcpz radiation, closely related to HIV-1 groups O and P, and clustered according to their field site of origin. At one site, there was evidence for intergroup transmission and a high intragroup prevalence. These isolated hot spots of SIVgor-infected gorilla communities could serve as a source for human infection. The overall low prevalence and sporadic distribution of SIVgor could suggest a decline of SIVgor in wild populations, but it cannot be excluded that SIVgor is still more prevalent in other parts of the geographical range of gorillas. [ABSTRACT FROM AUTHOR]

An abstract of the article "Origin of the human malaria parasite Plasmodium falciparum in gorillas" that was presented at a conference titled "From Parasite to Prevention: Advances in the understanding of malaria" held in Edinburgh, Great Britain on October 20-22, 2010, is presented.