This chert flake was made by Kanzi, a bonobo, during experiments in 1994 to see if apes are capable of controlled stone flaking. The flake was struck from a core by Kanzi, who handed it to the archaeologist Iain Davidson, as discussed in his coauthored 1996 book, Human Evolution, Language and Mind.
Kanzi making stone flakes in 1994. Photo courtesy of Iain Davidson.
The flake is split down the percussion axis by a ‘siret’ fracture and the other half is missing. The siret fracture and stacked compression rings suggest more force was used to strike the flake than was necessary. The hinge termination on the lateral margin of the flake is unusual, and may be due to striking the flake into a hollow on the core face rather than down a well-defined zone of high mass. A negative scar from a prior flake removed in the same direction is visible on the dorsal face. The core face was short, and the flake propagated completely through it and removed cortex on the surface opposite the platform. The platform is single-facet—probably a negative flake scar from a prior removal—suggesting that the core was rotated at least once. The blow was delivered well-back from the platform edge. The exterior platform angle is less than 90 degrees, thus satisfying the ‘acute angle rule’ for successful flake removal. Overall, the flake may indicate some knowledge of platforms and flake-making, but incomplete awareness of the core mass relationship and the force necessary to control flake propagation.
The flake is part of the Archaeology and Palaeoanthropology teaching collection, University of New England.
Research into the stone-flaking capabilities of bonobos was initiated by the primatologist Sue Savage-Rumbaugh and the archaeologists Nicholas Toth and Kathy Schick in 1990. The subject was Kanzi, a bonobo born at the Yerkes Field Station in Georgia in 1980. The goal was to gauge the degree to which great apes were capable of the manual and cognitive tasks necessary for controlled flaking. The experimental design involved hiding food in a box secured by rope as an incentive for Kanzi to create a sharp-edged flake to cut the string. It was found that although Kanzi could make sharp flakes and fragments to compete the task, he was incapable of recognising the basic aspects of controlled stone-flaking, despite intensive instruction by Toth, a stone-flaking expert. This suggests that the cognitive and manual abilities necessary for controlled stone-flaking arose after our evolutionary divergence from the great apes, ca. 5 million years ago. These abilities probably first appeared in our own genus, Homo.
