Table 1 Summary table of the strengths and limitations of using different primate species as models of early hominin stone behaviours as well as a description of the most appropriate use of each species in comparative studies aimed at reconstructing early hominin stone repertoires.

Chimpanzees (Pan troglodytes)

• Close phylogenetic ties to humans (Langergraber et al., 2012)

• Large body of research on both wild and captive chimpanzee behaviours

• Most extensive tool use repertoires among primates (Whiten et al., 1999)

• Some (but not all) populations use stone tools for percusssive behaviours, including some present in modern humans

• 6 Ma of independent evolution from hominins (e.g., Sayers et al., 2012)

• Difference in behaviour across chimpanzee subspecies; therefore no ‘one’ chimpanzee model

• No evidence of intentional or systematic sharp stone production

• Extant chimpanzees live in different environments to early hominins or the LCA (Sayers et al., 2012)

• Percussive stone foraging behaviours, particularly nut-cracking and its signature in archaeological artefacts

Bonobos (Pan paniscus)

• Close phylogenetic ties to humans (Langergraber et al., 2012)

• Have the ability to use tools (Gruber and Clay, 2016), including stone tools (Neufuss et al., 2017)

• Much less intensive research effort on bonobos than chimpanzees

• Rarely use tools and have a much smaller tool use repertoire

• Currently the only study on bonobo stone tool manufacture and use tested enculturated bonobos, limiting the conclusions that can be drawn at the species level

• Drawing more robust conclusions about the stone tool using abilities of the Pan-Homo LCA (Dual-Pan model; Gruber and Clay, 2016)

• Hominin species that had the ability to use tools but did not express it

Orangutans (Pongo abelii)

• Second most extensive tool use repertoires among primates, after chimpanzees (van Schaik et al., 2003)

• Engage in lithic and non-lithic percussive behaviour in captivity (Motes-Rodrigo et al., 2022; Bandini et al., 2021)

• Oldest common ancestor between hominins and non-human great apes (~13 Ma, Glazco and Nei, 2003)

• No currently known stone tool behaviours in the wild

• Reconstructing the tool use repertoires of hominoid species that lived in the forest canopy and rarely foraged on the ground, as well as of more solitary species

Gorillas (Gorilla gorilla)

• Have the ability to use tools in captivity (e.g. Lonsdorf et al., 2009)

• Distantly related to humans (~7 Ma, Glazco and Nei, 2003)

• Rarely use tools in the wild

• No evidence yet for stone tool use (Bandini and Tennie, 2020)

• Comparative studies with stone tool using great apes

Modern Humans (Homo sapiens)

• Very closely related to various early hominin species

• Easily accessible as test subjects

• Can instruct subjects as to the aims and requirements of the study

• Can test children and traditional stone knapper communities for cross-cultural and ontogenetic studies

• Engage in intentional sharp-edged stone detachment and lithic percussive behaviours

• Most easily accessible test subjects are from predominantly WEIRD backgrounds, limiting the ability to generalise findings to all populations (Henrich et al., 2010)

• Certain cognitive mechanisms present in modern humans are likely the result of cultural rather than genetic evolution (Heyes, 2018), meaning that they may have been absent or much less developed in our hominin ancestors

• The vast majority of modern human cultures do not make or use early stone tools any more

• Studies of contemporary stone tool use have generally been conducted with sedentary populations, whereas our ancestors during most of our evolutionary history were mobile foragers

• Hominin knapping (particularly studies with non-WEIRD populations)

• Hominin lithic percussion (particularly studies with non-WEIRD populations)

Macaques (Macaca fascicularis)

• Some subspecies use stone tools to forage for food in coastal environments (e.g., Gumert et al., 2009), including behaviours that are, or used to be, present in traditional stone knapping communities (Tindale, 1977)

• Present a repertoire of stone tool use behaviours

• Distantly related to humans (~23 Ma, Glazco and Nei, 2003)

• Most macaque species do not use stone tools

• Reconstructing stone percussive repertoires in coastal environments (Gumert and Malaivijitnond, 2012)

• Further understanding of early hominin nut cracking and its signature in archaeological artefacts

Capuchins (Sapajus libidinosus/apella)

• Extensive tool use repertoires including the widest range of stone tool use repertoires of all tool-using primates (Arroyo et al., 2021)

• Evidence for dissociated sharp stone production and use abilities in captive capuchins and some evidence for intentional sharp stone tool production in captivity (Westergaard and Suomi, 1994)

• Distantly related to humans and other great apes (~33 Ma, Glazco and Nei, 2003)

• No evidence of intentional or systematic sharp stone production in the wild

• Initial stages of hominin lithic technologies (knapping) and precursors of intentional stone tool manufacture

• Potential diversity of behaviours included in the early hominin stone tool use repertoire

• Further understanding of early hominin percussive behaviours (e.g. nut cracking) and their signature in archaeological artefacts

Other animals

• Various species use stone tools, including for percussion

• Provide a different perspective on stone tool use (e.g., outgroup)

• Very distantly related to humans, therefore inferences based on phylogenetic similarities cannot be made

• Often these animals live in very different environments to early hominins

• Further insight into the conditions behind the emergence of stone tool use in animals with different environmental pressures and cognitive demands/abilities