Figure 2. Photographs and stills of accumulative stone throwing behaviour and sites.
(a) Adult male chimpanzee tossing a stone; hurling a stone (Boé, Guinea-Bissau); and banging a stone (Comoé GEPRENAF, Côte d’Ivoire). (b) Boé, Guinea-Bissau landscape: stones accumulated in a hollow tree; a chimpanzee accumulative stone throwing site; and stones accumulated in-between buttress roots (see also Supplementary Movies 1–7).