![]() ![]() Hopkins et al., 2009), termite nests visited by chimpanzees in natural habitats are typically larger, more complex structurally, and more variable in many dimensions (e.g., shape, size, and friability of the nest, as well as termite species, density, accessibility, and response) than the simulations achieved in captive studies. Although there have been experimental analyses of chimpanzees' fishing in captivity using simulations of termite nests (e.g. ( 2015).Ĭhimpanzees learn to fish for termites with others in a socially aided setting (i.e., it is a tradition Lonsdorf, 2005 Musgrave et al., 2016 Whiten et al., 2001). Thus, the manual skills evident during termite fishing differ in character from those evident during feeding on large fruits and meat, as described, for example, by Marzke et al. ![]() The chimpanzee must control the spatial relation between the probe and the termite nest, rather than its own body. ![]() The goal is to use the object as it is the task requires delicate movements, not forceful grips. In termite fishing, the gripped object is not explicitly modified when in use as a probe, but it is repaired or discarded if it becomes damaged. Previous reports of hand movements and grips in wild apes have examined actions used during food-processing, where the handled object is modified for ingestion (e.g., Marzke, 1971 Marzke et al., 2015). Termite fishing is a good candidate behavior for examining details of manual dexterity, as such actions are well-practiced in adult individuals and one can measure the outcomes of the actions in a variety of dimensions (e.g., rates of feeding failed attempts etc.) (e.g., Bardo et al., 2017 Mangalam & Fragaszy, 2015). The work contributes to the eventual goal of understanding the dimensions and degrees of chimpanzees' dexterity in this activity. In this study, we describe the repertoire of manual actions used in termite fishing by adult and subadult female chimpanzees in the Goualougo Triangle (Sanz & Morgan, 2007 Sanz et al., 2009). To date, the actions chimpanzees use when fishing for termites have been described in very general terms, and little is known about the dexterity expressed in this activity. This behavior is theoretically important to primatologists and other behavioral scientists as traditions vary across chimpanzee populations (Musgrave et al., 2016 Whiten et al., 2001), and because of the potential contributions to chimpanzees' diet conferred by access to this resource (e.g., Deblauwe & Janssens, 2008 O'Malley & Power, 2012). From eastern to western Africa, wild chimpanzees habitually fish for termites from epigeal (above ground) nests (Mcgrew et al., 1979 Sanz et al., 2004). The termites are then consumed by the chimpanzee (Nishida et al., 1999). Termite fishing is defined as the insertion of a probe (grass, twig, bark, stem, vine, etc.) into a termite nest and withdrawal of the probe with soldiers attached to it by their pinching mandibles. Termite fishing in chimpanzees (first described by Goodall, 1964) is one of the most widely known examples of tooling ( sensu Fragaszy & Mangalam, 2018) by a nonhuman animal. Additional research on digital function and on environmental, organismic, and task constraints will further reveal manual dexterity in termite fishing. 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. The sliding technique requires complementary bimanual coordination (extracting with one hand and grasping lightly with the other, at the same time). We describe a third technique: sliding the probe between the digits of one stationary hand as the probe is extracted from the nest. Chimpanzees have been described as eating termites in two ways-directly from the probe or by sweeping them from the probe with one hand. ![]() 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. Six chimpanzees used exclusively one hand (left or right) to grip the probe during termite fishing. 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. 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. ![]()
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