First GIS Analysis of Modern Stone Tools Used by Wild Chimpanzees (Pan troglodytes verus) in Bossou,Guinea, West Africa

Stone tool use by wild chimpanzees of West Africa offers a unique opportunity to explore the evolutionary roots of technology during human evolution. However, detailed analyses of chimpanzee stone artifacts are still lacking, thus precluding a comparison with the earliest archaeological record. This paper presents the first systematic study of stone tools used by wild chimpanzees to crack open nuts in Bossou (Guinea-Conakry), and applies pioneering analytical techniques to such artifacts. Automatic morphometric GIS classification enabled to create maps of use wear over the stone tools (anvils, hammers, and hammers/ anvils), which were blind tested with GIS spatial analysis of damage patterns identified visually. Our analysis shows that chimpanzee stone tool use wear can be systematized and specific damage patterns discerned, allowing to discriminate between active and passive pounders in lithic assemblages. In summary, our results demonstrate the heuristic potential of combined suites of GIS techniques for the analysis of battered artifacts, and have enabled creating a referential framework of analysis in which wild chimpanzee battered tools can for the first time be directly compared to the early archaeological record.     

Use of tool sets by chimpanzees for multiple purposes in Moukalaba-Doudou National Park,Gabon

We report our recent findings on the use of tool sets by chimpanzees in Moukalaba-Doudou National Park, Gabon. Direct observations and evidences left by chimpanzees showed that chimpanzees used sticks as pounders, enlargers, and collectors to extract honey from beehives of stingless bees (Meliponula sp.), which may correspond to those previously found in the same site for fishing termites and to those found in Loango National Park, Gabon. However, we observed chimpanzees using a similar set of tools for hunting a medium-sized mammal (possibly mongoose) that hid inside a log. This is the first report of hunting with tools by a chimpanzee population in Central Africa. Chimpanzees may recognize the multiple functions and applicability of tools (extracting honey and driving prey), although it is still a preliminary speculation. Our findings may provide us a new insight on the chimpanzee’s flexibility of tool use and cognitive abilities of complex food gathering.     

The Number of Cultural Traits Is Correlated with Female Group Size but Not with Male Group Size in Chimpanzee Communities

What determines the number of cultural traits present in chimpanzee (Pan troglodytes) communities is poorly understood. In humans, theoretical models suggest that the frequency of cultural traits can be predicted by population size. In chimpanzees, however, females seem to have a particularly important role as cultural carriers. Female chimpanzees use tools more frequently than males. They also spend more time with their young, skewing the infants'' potential for social learning towards their mothers. In Gombe, termite fishing has been shown to be transmitted from mother to offspring. Lastly, it is female chimpanzees that transfer between communities and thus have the possibility of bringing in novel cultural traits from other communities. From these observations we predicted that females are more important cultural carriers than males. Here we show that the reported number of cultural traits in chimpanzee communities correlates with the number of females in chimpanzee communities, but not with the number of males. Hence, our results suggest that females are the carriers of chimpanzee culture.     

Invention and modification of a new tool use behavior: ant-fishing in trees by a wild chimpanzee (Pan troglodytes verus) at Bossou, Guinea

Wild chimpanzees are known to have a different repertoire of tool use unique to each community. For example, "ant-dipping" is a tool use behavior known in several chimpanzee communities across Africa targeted at driver ants (Dorylus spp.) on the ground, whereas "ant-fishing," which is aimed at carpenter ants (Camponotus spp.) in trees, has primarily been observed among the chimpanzees of Mahale in Tanzania. Although the evidence for differences between field sites is accumulating, we have little knowledge on how these tool use behaviors appear at each site and on how these are modified over time. This study reports two"ant-fishing" sessions which occurred 2 years apart by a young male chimpanzee at Bossou, Guinea. Ant-fishing had never been observed before in this community over the past 27 years. During the first session, at the age of 5, he employed wands of similar length when ant-fishing in trees to those used for ant-dipping on the ground, which is a customary tool use behavior of this community. Two years later, at the age of 7, his tools for ant-fishing were shorter and more suitable for capturing carpenter ants. This observation is a rare example of innovation in the wild and does provide insights into problem-solving and learning processes in chimpanzees.     

Chimpanzee tool technology in the Goualougo Triangle, Republic of Congo

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.     

The Role of Behavioral Research in the Conservation of Chimpanzees and Gorillas

Chimpanzees and gorillas are among man's closest living relatives, sharing most of the human genetic code and having many similarities to humans in anatomy, physiology, and behavior. Like humans, these apes make and use tools and have strong family bonds. Chimpanzees even show population-specific behaviors similar to those of human cultures. However, chimpanzee and gorilla populations are in dramatic decline due to bushmeat hunting, habitat loss, and the varied risks of small, isolated populations. The first step in conserving the world's ape populations in the wild is to recognize and understand the complexities of these threats. Mitigating the risks takes a deeper understanding of ape behavior. This article provides examples of how gorilla and chimpanzee behavioral studies intersect with, and are critical to, conservation efforts.     

A comprehensive atlas of white matter tracts in the chimpanzee

Chimpanzees (Pan troglodytes) are, along with bonobos, humans’ closest living relatives. The advent of diffusion MRI tractography in recent years has allowed a resurgence of comparative neuroanatomical studies in humans and other primate species. Here we offer, in comparative perspective, the first chimpanzee white matter atlas, constructed from in vivo chimpanzee diffusion-weighted scans. Comparative white matter atlases provide a useful tool for identifying neuroanatomical differences and similarities between humans and other primate species. Until now, comprehensive fascicular atlases have been created for humans (Homo sapiens), rhesus macaques (Macaca mulatta), and several other nonhuman primate species, but never in a nonhuman ape. Information on chimpanzee neuroanatomy is essential for understanding the anatomical specializations of white matter organization that are unique to the human lineage.

Diffusion MRI tractography reveals the first complete atlas of white matter of the chimpanzee, with the potential to help understand differences between the organization of human and chimpanzee brains.     

Cassava Bacterial Blight: Using Genomics for the Elucidation and Management of an Old Problem

Bacterial Blight is an important disease of cassava, causing losses that have resulted in historical famines in certain growing zones. The disease is caused by Xanthomonas axonopodis pv. manihotis, a gram-negative rod that belongs to the gammaproteobacteria. In this review, we describe the pathosystem and the recent studies that have been undertaken to elucidate both susceptibility and resistance mechanisms in cassava, with the hope of generating resistant plants using biotechnology. We first describe studies of the pathogen, including pathogen population changes through time as well as genomic tools that have recently been generated to determine pathogenicity factors. Secondly, we discuss mechanisms of disease resistance that have been elucidated in recent years and how these mechanisms could be used for the generation of improved plants resistant to CBB.     

Is primate tool use special? Chimpanzee and New Caledonian crow compared

The chimpanzee (Pan troglodytes) is well-known in both nature and captivity as an impressive maker and user of tools, but recently the New Caledonian crow (Corvus moneduloides) has been championed as being equivalent or superior to the ape in elementary technology. I systematically compare the two taxa, going beyond simple presence/absence scoring of tool-using and -making types, on four more precise aspects of material culture: (i) types of associative technology (tools used in combination); (ii) modes of tool making; (iii) modes of tool use; and (iv) functions of tool use. I emphasize tool use in nature, when performance is habitual or customary, rather than in anecdotal or idiosyncratic. On all four measures, the ape shows more variety than does the corvid, especially in modes and functions that go beyond extractive foraging. However, more sustained field research is required on the crows before this contrast is conclusive.     

The use of “second rate” raw materials during Middle Palaeolithic. Technological and functional analysis of two sites in north-eastern Iberia

In recent years many issues arose regarding the technological and functional analysis of lithic assemblages dominated by “second rate raw materials” like vein quartz, metamorphic or volcanic rocks. Nevertheless, the technological study of this kind of assemblages and their consequent interpretation seems to be still based on the techno-typological criteria elaborated for flint artefacts, thus leading to the common inference that these lithic assemblages are archaic and mainly linked to opportunistic production systems. Pedra Dreta and Can Garriga, located in the north-east of the Iberian Peninsula, present two small lithic assemblages dominated by local raw materials (vein quartz, quartzite, porphyry, syenite, etc.) and by opportunistic reduction sequences but with the presence of Levallois and discoid châine operatoires. The technological analysis is aimed to answer two main issues that emerged during the study and that can contribute to the study of non-flint lithic assemblages: 1. Which criteria should we adopt to distinguish between discoid and recurrent centripetal Levallois products? 2. Is it possible that the Levallois products are the result rather of the opportunistic and expedient reduction sequences that are dominant in these assemblages than of a real use of the Levallois method? A use-wear analysis has also been conducted for the first time on Pedra Dreta and Can Garriga lithic assemblages. The peculiarities of the lithic raw materials employed made necessary the adoption of specific methodologies and the realization of a particular procedure for the analysis of porphyry's tools.     

Activity profiles and hook-tool use of New Caledonian crows recorded by bird-borne video cameras

New Caledonian crows are renowned for their unusually sophisticated tool behaviour. Despite decades of fieldwork, however, very little is known about how they make and use their foraging tools in the wild, which is largely owing to the difficulties in observing these shy forest birds. To obtain first estimates of activity budgets, as well as close-up observations of tool-assisted foraging, we equipped 19 wild crows with self-developed miniature video cameras, yielding more than 10 h of analysable video footage for 10 subjects. While only four crows used tools during recording sessions, they did so extensively: across all 10 birds, we conservatively estimate that tool-related behaviour occurred in 3% of total observation time, and accounted for 19% of all foraging behaviour. Our video-loggers provided first footage of crows manufacturing, and using, one of their most complex tool types—hooked stick tools—under completely natural foraging conditions. We recorded manufacture from live branches of paperbark (Melaleuca sp.) and another tree species (thought to be Acacia spirorbis), and deployment of tools in a range of contexts, including on the forest floor. Taken together, our video recordings reveal an ‘expanded’ foraging niche for hooked stick tools, and highlight more generally how crows routinely switch between tool- and bill-assisted foraging.     

Chromosomal Inversions between Human and Chimpanzee Lineages Caused by Retrotransposons

The long interspersed element-1 (LINE-1 or L1) and Alu elements are the most abundant mobile elements comprising 21% and 11% of the human genome, respectively. Since the divergence of human and chimpanzee lineages, these elements have vigorously created chromosomal rearrangements causing genomic difference between humans and chimpanzees by either increasing or decreasing the size of genome. Here, we report an exotic mechanism, retrotransposon recombination-mediated inversion (RRMI), that usually does not alter the amount of genomic material present. Through the comparison of the human and chimpanzee draft genome sequences, we identified 252 inversions whose respective inversion junctions can clearly be characterized. Our results suggest that L1 and Alu elements cause chromosomal inversions by either forming a secondary structure or providing a fragile site for double-strand breaks. The detailed analysis of the inversion breakpoints showed that L1 and Alu elements are responsible for at least 44% of the 252 inversion loci between human and chimpanzee lineages, including 49 RRMI loci. Among them, three RRMI loci inverted exonic regions in known genes, which implicates this mechanism in generating the genomic and phenotypic differences between human and chimpanzee lineages. This study is the first comprehensive analysis of mobile element bases inversion breakpoints between human and chimpanzee lineages, and highlights their role in primate genome evolution.     

The chimpanzee of Filabanga,western Tanzania

The chimpanzee (Pan troglodytes) of western Tanzania is found in one of the driest habitats of this species where openland vegetation, especially theBrachystegia, Julbernardia, andIsoberlinia woodlands, is dominant, while the evergreen or semi-evergreen rain forests (the riverine forests) are less developed, being confined to river basins. The chimpanzee seems to adapt to this dry country better than any of the other forest primates living there. The results of the study in Filabanga indicate that there are some methods of adaptation which enable the chimpanzee to survive in this harsh environment.

1. The chimpanzee uses openland vegetation to a comparatively large extent. TheBrachystegia bussei woodland especially, is utilized as a habitual nesting place and doubtless as an important feeding place.
2. In the Masito Hills, which comprises Filabanga, the localities where food is abundant change seasonally. The chimpanzees migrate over a wide range, estimated to be between 200 and 400 square kilometers, from an area where food has become scarce to an area where food is plentiful.
3. Areas where food is plentiful are shared by two or more unit groups of chimpanzee.
4. The grouping patterns of the chimpanzee enable it to utilize both the areas where food is scarce and those where it is abundant.

     

“Stepping-sticks” and “seat-sticks”: New types of tools used by wild chimpanzees (Pan troglodytes) in Sierra Leone

In Tenkere, Sierra Leone, a community of wild chimpanzees (Pan troglodytes verus) spent long hours eating the fruits and flowers of the Kapok (Ceiba pentandra) tree. The branches of this species are covered in sharp thorns which make movement in their high canopies problematic for the chimpanzees. In an apparent attempt to increase their mobility and to ease the discomfort of lengthy bouts of eating in these trees, some of the Tenkere chimpanzees have been observed using stick tools as foot (“stepping-sticks”) and body (“seat-sticks”) protection against the painful thorns. This form of tool-using is culturally unique to the Tenkere chimpanzees, as at other sites where these apes have been observed eating parts of kapok trees, there are no published records of this tool technology. In three of the stepping-stick tool use incidents, the chimpanzee used the tool(s), held between their greater and lesser toes, in locomotion. This form of tool use is the first recorded case of habitually used tools that can be justifiably categorized as being “worn” by any known wild population of Pan troglodytes. Am J Primatol 41:45–52, 1997. © 1997 Wiley-Liss, Inc.     

Savanna chimpanzees, Pan troglodytes verus, hunt with tools

Although tool use is known to occur in species ranging from naked mole rats [1] to owls [2], chimpanzees are the most accomplished tool users [3-5]. The modification and use of tools during hunting, however, is still considered to be a uniquely human trait among primates. Here, we report the first account of habitual tool use during vertebrate hunting by nonhumans. At the Fongoli site in Senegal, we observed ten different chimpanzees use tools to hunt prosimian prey in 22 bouts. This includes immature chimpanzees and females, members of age-sex classes not normally characterized by extensive hunting behavior. Chimpanzees made 26 different tools, and we were able to recover and analyze 12 of these. Tool construction entailed up to five steps, including trimming the tool tip to a point. Tools were used in the manner of a spear, rather than a probe or rousing tool. This new information on chimpanzee tool use has important implications for the evolution of tool use and construction for hunting in the earliest hominids, especially given our observations that females and immature chimpanzees exhibited this behavior more frequently than adult males.     

Design complexity in termite-fishing tools of chimpanzees (Pan troglodytes)

Adopting the approach taken with New Caledonian crows (Corvus moneduloides), we present evidence of design complexity in one of the termite-fishing tools of chimpanzees (Pan troglodytes) in the Goualougo Triangle, Republic of Congo. Prior to termite fishing, chimpanzees applied a set of deliberate, distinguishable actions to modify herb stems to fashion a brush-tipped probe, which is different from the form of fishing tools used by chimpanzees in East and West Africa. This means that ‘brush-tipped fishing probes’, unlike ‘brush sticks’, are not a by-product of use but a deliberate design feature absent in other chimpanzee populations. The specialized modifications to prepare the tool for termite fishing, measures taken to repair non-functional brushes and appropriate orientation of the modified end suggest that these wild chimpanzees are attentive to tool modifications. We also conducted experimental trials that showed that a brush-tipped probe is more effective in gathering insects than an unmodified fishing probe. Based on these findings, we suggest that chimpanzees in the Congo Basin have developed an improved fishing probe design.