Professor of Psychology, Chair of Behavioral and Brain Science Program, University of Georgia
“Hercules with a tail: Stone tool use in wild bearded capuchin monkeys”
THURSDAY, February 9 @ 12pm
in BPSB 122
ABSTRACT: Wild capuchin monkeys living in Fazenda Boa Vista (Piauí, Brazil; a dry forest habitat) routinely use stone hammers to crack open very resistant palm nuts after they place the nuts on stone or log anvils. Capuchin monkeys transport nuts and stones to anvils, then strike the nuts to crack them, an impressive accomplishment given that the monkeys as adults weigh 1.8 – 4.4 kg, and the stones they use can weigh up to 3 kg. The monkeys display careful choice of nuts, hammer stones and anvils, and finely honed skill in cracking the nuts, including precise positioning of the nut on the anvil, precise handling of the stone hammer, precise control of the trajectory of their strikes and modulation of the force of their strikes in accord with the condition of the nut following the previous strike. Indeed, capuchin monkeys crack nuts in fewer strikes than novice humans. These features of tool use are unexpected in nonhuman primates, let alone small monkeys from South America, according to conventional views of physical and cognitive correlates of stone tool use. Stone tool use by capuchin monkeys opens up a new reference point for understanding the embodied nature of skilled tool use.