Chimpanzee carrying behaviour and the origins of human bipedality
Susana Carvalho, Dora Biro, Eugénia Cunha, Kimberley J. Hockings, William C. McGrew, Brian G. Richmond, Tetsuro MatsuzawaDOI: 10.1016/j.cub.2012.01.052
Figure 1. Bipedal transport of items by wild chimpanzees. (A) Adult male carries both anvil and hammer stones (anvil in left hand, hammer in left foot) and Coula edulis nuts (in mouth and right hand) during an experimental nut-cracking session, before depositing items and starting to crack nuts. Inset shows two species of nuts presented at outdoor laboratory (left: Elaeis guineensis, right: Coula edulis) (see also Supplemental Movie S1). (B) Adult male carries three papayas (one in each hand and one in mouth) during crop-raiding (see also Supplemental Movie S2).
Video clip shows bipedal transport of nuts and stone tools by adult male chimpanzee at Bossou's outdoor laboratory. He first gathers up a whole pile of 20 Coula edulis nuts, using both hands and mouth, then walks bipedally to set of stone tools provided, where he first selects stone anvil (carried in left hand) then stone hammer (carried in left foot). He then continues to walk bipedally, moving to different spot, where he stops to process nuts and to consume their kernels. While walking bipedally during final stage of transport, he uses three limbs, as well as mouth, to carry nuts and stone tools.
Video clip shows transport of three papayas by adult male chimpanzee at Bossou. Fruits were collected from small orchard in village and transported back to forest. Items are carried in both hands and mouth. Transport includes quadrupedal, tripedal and bipedal locomotion, with 17 of 38 steps being bipedal.