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increasing their access to key resources, such as food or mates.1-5 Alternatively, it has 5 been argued to be a non-adaptive result of human impacts, such as habitat destruction 6 or provisioning of food. [6][7][8][9] To discriminate between these hypotheses we compiled long-7 term information from 18 chimpanzee communities and 4 bonobo communities. Our 8 data include 152 killings (N=58 observed, 41 inferred, and 53 suspected killings) by 9 chimpanzees in 15 communities and one suspected killing by bonobos. We found that 10 males had the greatest involvement as attackers (92% of participants) and victims 11 (73%); most killings (66%) involved intercommunity attacks; and attackers greatly 12 outnumbered their victims (median 8:1 ratio). Variation in rates of killing among 13communities depended on demographic variables but was unrelated to measures of 14 human impacts. These results from all major study populations over the last five 15 decades are consistent with previously proposed adaptive explanations for killing by 16 chimpanzees but not with the human impact hypothesis. 17 18Conspecific killing has been documented at multiple chimpanzee study sites, 2-5,10-12 but rates 19 vary greatly among sites. The human impact hypothesis and the adaptive strategies 20 hypothesis yield contrasting predictions, which we test here (Tables 1, 2). The human impact 21 hypothesis states that killing occurs mainly as an incidental outcome of aggression, 22 exacerbated by human activities such as providing a concentrated food resource, 23 deforestation-induced crowding, anthropogenic diseases or hunting. Accordingly, lethal 24 aggression should be high where human disturbance is high. In contrast, the adaptive strategies hypothesis views aggression as an evolved strategic 27 response by which aggressors tend to increase their fitness through increased access to 28 territory, food, mates or other benefits. [1][2][3][4][5][10][11][12][13][14][15][16][17] 45Intracommunity infanticide by females may result from intense competition among females 46 for the best feeding areas.17 Population differences in rates of killing are accordingly 47 expected to result from socioecological factors such as differences in grouping patterns 2,11 48 and/or demography.14 Lethal aggression thus occurs within a diverse set of circumstances, 49 but is expected to be most commonly committed by males; directed towards males; directed 50 6 towards non-kin, particularly members of other groups; and committed when overwhelming 51 numerical superiority reduces the costs of killing. 52 53Previous studies have developed and tested these specific hypotheses 2,5,[11][12][13][14][15][16][17] ; the present study 54 represents the first effort to test multiple hypotheses simultaneously with a comprehensive 55 dataset. To do so, we assembled data from 18 chimpanzee communities from both eastern 56 (N=12) and western (N=6) clades 24 of chimpanzees studied over 426 years (median = 21 57 years; range: 4-53) and from 4 bonobo communities studied for 92 years (media...

Plasmodium vivax is the leading cause of human malaria in Asia and Latin America but is absent from most of central Africa due to the near fixation of a mutation that inhibits the expression of its receptor, the Duffy antigen, on human erythrocytes. The emergence of this protective allele is not understood because P. vivax is believed to have originated in Asia. Here we show, using a non-invasive approach, that wild chimpanzees and gorillas throughout central Africa are endemically infected with parasites that are closely related to human P. vivax. Sequence analyses reveal that ape parasites lack host specificity and are much more diverse than human parasites, which form a monophyletic lineage within the ape parasite radiation. These findings indicate that human P. vivax is of African origin and likely selected for the Duffy-negative mutation. All extant human P. vivax parasites are derived from a single ancestor that escaped out of Africa.

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Aim: To predict the distribution of suitable environmental conditions (SEC) for eight African great ape taxa for a first time period, the 1990s and then project it to a second time period, the 2000s; to assess the relative importance of factors influencing SEC distribution and to estimate rates of SEC loss, isolation and fragmentation over the last two decades. Location: Twenty-two African great ape range countries. Methods: We extracted 15,051 presence localities collected between 1995 and 2010 from 68 different areas surveyed across the African ape range. We combined a maximum entropy algorithm and logistic regression to relate ape presence information to environmental and human impact variables from the 1990s with a resolution of 5 × 5 km across the entire ape range. We then made SEC projections for the 2000s using updated human impact variables. Results: Total SEC area was approximately 2,015,480 and 1,807,653 km2 in the 1990s and 2000s, respectively. Loss of predicted SEC appeared highest for Cross River gorillas (-59%), followed by eastern gorillas (-52%), western gorillas (-32%), bonobos (-29%), central chimpanzees (-17%) and western chimpanzees (-11%). SEC for Nigeria-Cameroon chimpanzees and eastern chimpanzees was not greatly reduced. Except for Cross River and eastern gorillas, the number of SEC patches did not change significantly, suggesting that SEC loss was caused mainly by patch size reduction. Main conclusions: The first continent-wide perspective of African ape SEC distribution shows dramatic declines in recent years. The model has clear limitations for use at small geographic scales, given the quality of available data and the coarse resolution of predictions. However, at the large scale it has potential for informing international policymaking, mitigation of resource extraction and infrastructure development, as well as for spatial prioritization of conservation effort and evaluating conservation effectiveness.Additional co-authors: Head, J.,Huijbregts, B., Lindsell, J., McLennan, M., Martinez, L., Morgan, D., N'Goran K.P., Ntongho, A., Petre, C.A., Regnaut, S., Sanz, C., Tondossama, A

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.

The gut microbiome can vary across differences in host lifestyle, geography, and host species. By comparing closely related host species across varying lifestyles and geography, we can evaluate the relative contributions of these factors in structuring the composition and functions of the microbiome. Here we show that the gut microbial taxa, microbial gene family composition, and resistomes of great apes and humans are more related by host lifestyle than geography. We show that captive chimpanzees and gorillas are enriched for microbial genera commonly found in non-Westernized humans. Captive ape microbiomes also had up to ~34-fold higher abundance and up to ~5-fold higher richness of all antibiotic resistance genes compared with wild apes. Through functional metagenomics, we identified a number of novel antibiotic resistance genes, including a gene conferring resistance to colistin, an antibiotic of last resort. Finally, by comparing our study cohorts to human and ape gut microbiomes from a diverse range of environments and lifestyles, we find that the influence of host lifestyle is robust to various geographic locations.

We quantify the impacts of poaching, Ebola, and habitat degradation on western lowland gorillas and central chimpanzees.