On the tool use behavior of the bonobo‐chimpanzee last common ancestor, and the origins of hominine stone tool use

Abstract

The last common ancestor (LCA) shared by chimpanzees (Pan troglodytes) and bonobos (P. paniscus) was an Early Pleistocene African ape, which, based on the behavior of modern chimpanzees, may be assumed to be a tool-using animal. However, the character of tool use in the Pan lineage prior to the 20th century is largely unknown. Here, I use available data on wild bonobo tool use and emerging molecular estimates of demography during Pan evolution to hypothesise the plausible tool use behavior of the bonobo-chimpanzee LCA (or "Pancestor") at the start of the Pleistocene, over 2 million years ago. This method indicates that the common ancestor of living Pan apes likely used plant tools for probing, sponging, and display, but it did not use stone tools. Instead, stone tool use appears to have been independently invented by Western African chimpanzees (P. t. verus) during the Middle Pleistocene in the region of modern Liberia-Ivory Coast-Guinea, possibly as recently as 200,000-150,000 years ago. If this is the case, then the LCA of humans and chimpanzees likely also did not use stone tools, and this trait probably first emerged among hominins in Pliocene East Africa. This review also suggests that the consistently higher population sizes of Central African chimpanzees (P. t. troglodytes) over the past million years may have contributed to the increased complexity of wild tool use seen in this sub-species today.

Naïve orangutans (Pongo abelii & Pongo pygmaeus) individually acquire nut-cracking using hammer tools

“…Furthermore, even if currently sharing similar environments, different chimpanzee populations may have lived in different environments in the past. For example, a period of food scarcity in one area might have encouraged the chimpanzees living there to explore alternative available food sources, thus increasing the probability that more individuals in these populations would develop nut-cracking (see also Haslam, 2014 who further argues that “opportunity” and “relative profitability” drove the emergence of nut-cracking in some populations of chimpanzees). This situation would increase other group members’ exposure to nuts and nut-cracking materials and would therefore enhance both their motivation and opportunities to individually reinnovate the nut-cracking behaviour (via individual learning and non-copying mechanisms such as local and stimulus enhancement; see Zentall, 2003 for definitions).…”

Primatologia e ciências sociais

“…Assim, a emergência do uso de ferramentas não pode mais ser chamada de "hominização". Acredita-se hoje que o antepassado comum partilhado por bonobos e chimpanzés, que viveu no Pleistoceno há aproximadamente 2 milhões de anos [16], provavelmente usava ferramentas feitas de folhas com o intuito de sinalizar, fazer prospecções e cavar, segundo dados moleculares levantados a partir da demografia das duas espécies. Já o uso de ferramentas líticas surgiu independentemente nas duas espécies.…”

Occasional, obligatory, and habitual stone tool use in hominin evolution

“…No other primate experiences such difficulties. Some nonhuman primates use tools, but most of them cope with life's challenges without recourse to technology. Human obligatory tool use is a derived condition resulting from strong, sustained, and directional selective pressure.…”