Bonobos — chimpanzees’ sister species — don’t get the credit they deserve as tool users.
Bonobos ranging through a sanctuary’s protected forests in the Democratic Republic of Congo crack nuts with stones nearly as well as wild chimps in other parts of Africa do, researchers report August 26 in the American Journal of Primatology. Wild bonobos have rarely been observed using any object as a tool and have never been reported to pound open nuts with stones.
All 18 adult and adolescent bonobos tracked during April and May 2015 cracked oil palm nuts with stones of various sizes that researchers had placed near oil palm trees, says a team led by Johanna Neufuss of the University of Kent, England. Bonobos chose pounding stones well-suited to busting palm oil nutshells. These animals employed 15 grips to hold nut-cracking stones, including 10 grips not previously observed in nonhuman primates. Several novel grips involved holding a stone with the thumb and one or a few fingers while bracing the tool against the palm.