The evolutionary proximity of the non-human great apes to us is often stressed in studies of animals, such as Kanzi, a bonobo (Pan paniscus) bred in captivity, that demonstrate their capacity to undertake tool-use and even utilize and comprehend language (Toth et al., 1993; Savage-Rumbaugh and Lewin, 1996; Schick et al., 1999). Likewise, studies of chimpanzees (Pan spp.) have highlighted the similarity of their emotional and empathetic capacities to those of humans (Parr et al., 2005; Campbell and de Waal, 2014). However, as noted by Savage- Rumbaugh and Lewin (1996), in palaeoanthropology and archaeology more broadly, the emergence of the hominin clade and, later, our species, is referenced in terms of the ‘chasm’ between ourselves and other extant great apes. Indeed, despite our genetic and behavioural proximity, extant non-human great ape taxa are often popularly characterized as living fossils of how we used to be. They are used as analogues for the subsistence and behaviour of the Last Common Ancestor (LCA) of humans and non-human great apes (Clutton-Brock and Harvey, 1977; Goodall, 1986; Foley and Lewin, 2004) and it is almost as if the fact that they still occupy the tropical environments in which these hominoids likely evolved (though see Elton, 2008) allows them to be treated as static comparisons (Figure 3.1). Since Darwin wrote the Descent of Man in 1871, the forests of the tropics, and their modern non-human great ape inhabitants, have tended to be perceived as being left behind as the hominin clade gained increasingly ‘human’ traits of tool-use, medium to large game hunting, and upright locomotion on open ‘savanna’ landscapes (Dart, 1925; Potts, 1998; Klein, 1999). From this perspective it is perhaps unsurprising that tropical forests are seen as alien to the genus Homo and its closest hominin ancestors.
From action to language: comparative perspectives on primate tool use, gesture and the evolution of human language