Crickette Sanz

African origin of the malaria parasite Plasmodium vivax

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.

Ecological and social correlates of chimpanzee tool use

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 genetic population structure of wild western lowland gorillas (Gorilla gorilla gorilla) living in continuous rain forest.

To understand the evolutionary histories and conservation potential of wild animal species it is useful to assess whether taxa are genetically structured into different populations and identify the underlying factors responsible for any clustering. Landscape features such as rivers may influence genetic population structure, and analysis of structure by sex can further reveal effects of sex‐specific dispersal. Using microsatellite genotypes obtained from noninvasively collected fecal samples we investigated the population structure of 261 western lowland gorillas (WLGs) (Gorilla gorilla gorilla) from seven locations spanning an approximately 37,000u2009km2 region of mainly continuous rain forest within Central African Republic (CAR), Republic of Congo and Cameroon. We found our sample to consist of two or three significantly differentiated clusters. The boundaries of the clusters coincided with courses of major rivers. Moreover, geographic distance detoured around rivers better‐explained variation in genetic distance than straight line distance. Together these results suggest that major rivers in our study area play an important role in directing WLG gene flow. The number of clusters did not change when males and females were analyzed separately, indicating a lack of greater philopatry in WLG females than males at this scale. Am. J. Primatol. 76:868–878, 2014.

The sampling scheme matters: Pan troglodytes troglodytes and P. t. schweinfurthii are characterized by clinal genetic variation rather than a strong subspecies break

Populations of an organism living in marked geographical or evolutionary isolation from other populations of the same species are often termed subspecies and expected to show some degree of genetic distinctiveness. The common chimpanzee (Pan troglodytes) is currently described as four geographically delimited subspecies: the western (P. t. verus), the nigerian-cameroonian (P. t. ellioti), the central (P. t. troglodytes) and the eastern (P. t. schweinfurthii) chimpanzees. Although these taxa would be expected to be reciprocally monophyletic, studies have not always consistently resolved the central and eastern chimpanzee taxa. Most studies, however, used data from individuals of unknown or approximate geographic provenance. Thus, genetic data from samples of known origin may shed light on the evolutionary relationship of these subspecies. We generated microsatellite genotypes from noninvasively collected fecal samples of 185 central chimpanzees that were sampled across large parts of their range and analyzed them together with 283 published eastern chimpanzee genotypes from known localities. We observed a clear signal of isolation by distance across both subspecies. Further, we found that a large proportion of comparisons between groups taken from the same subspecies showed higher genetic differentiation than the least differentiated between-subspecies comparison. This proportion decreased substantially when we simulated a more clumped sampling scheme by including fewer groups. Our results support the general concept that the distribution of the sampled individuals can dramatically affect the inference of genetic population structure. With regard to chimpanzees, our results emphasize the close relationship of equatorial chimpanzees from central and eastern equatorial Africa and the difficult nature of subspecies definitions.

Insect prey characteristics affecting regional variation in chimpanzee tool use.

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.

Origin of the human malaria parasite Plasmodium falciparum in gorillas

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.

The Interdigital Brace and Other Grips for Termite Nest Perforation by Chimpanzees of the Goualougo Triangle, Republic of Congo

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.

Tool Use in Animals: Index

List of contributors Part I. Cognition of Tool Use: 1. Three ingredients for becoming a creative tool-user J. Call 2. Ecology and cognition of tool use in chimpanzees C. Boesch 3. Chimpanzees plan their tool use R. W. Byrne, C. M. Sanz and D. B. Morgan Part II. Comparative Cognition: 4. Insight, imagination and invention: tool understanding in a non-tool-using corvid N. Emery 5. Why is tool use rare in animals? G. Hunt, R. Gray and A. Taylor 6. Understanding differences in the way human and non-human primates represent tools: the role of teleological-intentional information A. M. Ruiz and L. R. Santos 7. Why do woodpecker finches use tools? S. Tebbich and I. Teschke Part III. Ecology and Culture: 8. The social context of chimpanzee tool use C. M. Sanz and D. B. Morgan 9. Orangutan tool use and the evolution of technology E. J. M. Meulman and C. P. van Schaik 10. The EthoCebus project: stone tool use by wild capuchin monkeys E. Visalberghi and D. Fragaszy Part IV. Archaeological Perspectives: 11. From pounding to knapping: how chimpanzees can help us model hominin lithics S. Carvalho, T. Matsuzawa and W. C. McGrew 12. Early hominin social learning strategies underlying the use and production of bone and stone tools M. Caruana, F. dErrico and L. Backwell 13. Perspectives on stone tools and cognition in the early paleolithic record S. P. McPherron Index.

Tool Use in Animals: Comparative cognition

List of contributors Part I. Cognition of Tool Use: 1. Three ingredients for becoming a creative tool-user J. Call 2. Ecology and cognition of tool use in chimpanzees C. Boesch 3. Chimpanzees plan their tool use R. W. Byrne, C. M. Sanz and D. B. Morgan Part II. Comparative Cognition: 4. Insight, imagination and invention: tool understanding in a non-tool-using corvid N. Emery 5. Why is tool use rare in animals? G. Hunt, R. Gray and A. Taylor 6. Understanding differences in the way human and non-human primates represent tools: the role of teleological-intentional information A. M. Ruiz and L. R. Santos 7. Why do woodpecker finches use tools? S. Tebbich and I. Teschke Part III. Ecology and Culture: 8. The social context of chimpanzee tool use C. M. Sanz and D. B. Morgan 9. Orangutan tool use and the evolution of technology E. J. M. Meulman and C. P. van Schaik 10. The EthoCebus project: stone tool use by wild capuchin monkeys E. Visalberghi and D. Fragaszy Part IV. Archaeological Perspectives: 11. From pounding to knapping: how chimpanzees can help us model hominin lithics S. Carvalho, T. Matsuzawa and W. C. McGrew 12. Early hominin social learning strategies underlying the use and production of bone and stone tools M. Caruana, F. dErrico and L. Backwell 13. Perspectives on stone tools and cognition in the early paleolithic record S. P. McPherron Index.

Tool Use in Animals: Ecology and culture

List of contributors Part I. Cognition of Tool Use: 1. Three ingredients for becoming a creative tool-user J. Call 2. Ecology and cognition of tool use in chimpanzees C. Boesch 3. Chimpanzees plan their tool use R. W. Byrne, C. M. Sanz and D. B. Morgan Part II. Comparative Cognition: 4. Insight, imagination and invention: tool understanding in a non-tool-using corvid N. Emery 5. Why is tool use rare in animals? G. Hunt, R. Gray and A. Taylor 6. Understanding differences in the way human and non-human primates represent tools: the role of teleological-intentional information A. M. Ruiz and L. R. Santos 7. Why do woodpecker finches use tools? S. Tebbich and I. Teschke Part III. Ecology and Culture: 8. The social context of chimpanzee tool use C. M. Sanz and D. B. Morgan 9. Orangutan tool use and the evolution of technology E. J. M. Meulman and C. P. van Schaik 10. The EthoCebus project: stone tool use by wild capuchin monkeys E. Visalberghi and D. Fragaszy Part IV. Archaeological Perspectives: 11. From pounding to knapping: how chimpanzees can help us model hominin lithics S. Carvalho, T. Matsuzawa and W. C. McGrew 12. Early hominin social learning strategies underlying the use and production of bone and stone tools M. Caruana, F. dErrico and L. Backwell 13. Perspectives on stone tools and cognition in the early paleolithic record S. P. McPherron Index.