Dexterity and technique in termite fishing by chimpanzees (Pan troglodytes troglodytes) in the Goualougo Triangle, Republic of Congo

Abstract

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.

Innovative composite tool use by Goffin’s cockatoos (Cacatua goffiniana)

“…The broad spectrum of individual strategies employed by our subjects further supports the notion that the Goffin's tooling capacities are spontaneously innovated and are based on domain general processing rather than on stereotyped, inherited behavioural routines [30][31][32][33] . This is reminiscent of the interindividual variability described in other flexible tool users such as chimpanzees, with different techniques in the use of the probe used to fish for termites in Goualougo, Republic of Congo 34 .…”

Chimpanzees use social information to acquire a skill they fail to innovate

“…The required sequence was modelled after naturally occurring behaviour in which chimpanzees bring tools to foraging sites. For instance, when chimpanzees fish for termites, they go through a sequence involving collecting a probe (such as a suitable branch), opening a hole in the termite mound, inserting and extracting the probe, and collecting the termites 41 , 42 . The required sequence thus followed a vending-machine principle involving three main steps: (1) a wooden ball needed to be retrieved, (2) a drawer in the apparatus needed to be pulled out and kept protruded, and (3) the ball needed to be inserted into a cavity of the pulled-out drawer.…”

Ticks, Hair Loss, and Non-Clinging Babies: A Novel Tick-Based Hypothesis for the Evolutionary Divergence of Humans and Chimpanzees

“…For example, given that ungulates have evolved immunologic [ 189 ] and oral grooming [ 190 ] defences against ticks, it is possible that hair loss (given other disadvantages) may not have provided sufficient benefit to promote this evolutionary pathway. By contrast, hominin hair loss would have evolved in a tick-naïve arboreal primate possessing a high level of manual dexterity [ 191 ] and visual acuity [ 192 ]. Accepting low social grooming times in early hominins (conserved from the LCA), hair loss in the hominin lineage may have provided a selective advantage by revealing otherwise concealed ticks [ 34 ].…”