Rock-throwing zoo chimp

stocked ammo in advance: study

March 10, 2009
Courtesy Cell Press
and World Science staff

Re­search­ers have found what they call some of the first un­am­big­u­ous ev­i­dence that an an­i­mal oth­er than hu­mans can make spon­ta­ne­ous plans for fu­ture events.

The re­port in the March 9 is­sue of the re­search jour­nal Cur­rent Bi­ol­o­gy high­lights a dec­ade of ob­serva­t­ions in a zoo of a male chim­pan­zee calmly col­lect­ing stones and fash­ion­ing con­crete discs that he would lat­er hurl at zoo vis­i­tors.

The chimp Santino at the Fu­ru­vik Zoo in Swe­den clutches a stone in his left hand in preparation for a launch. (Im­age cour­tesy Cell Press/Ma­thi­as Os­vath)

“These ob­serva­t­ions con­vinc­ingly show that our fel­low apes do con­sid­er the fu­ture in a very com­plex way,” said Ma­thi­as Os­vath of Lund Uni­ver­s­ity in Swe­den.

“It im­plies that they have a highly de­vel­oped con­scious­ness, in­clud­ing life-like men­tal sim­ula­t­ions of po­ten­tial events. They most prob­ab­ly have an ‘in­ner world’ like we have when re­view­ing past episodes of our lives or think­ing of days to come. When wild chimps col­lect stones or go out to war, they prob­ab­ly plan this in ad­vance. I would guess that they plan much of their ever­yday be­hav­ior.”

The chimp, named Santi­no, lived dur­ing the events at the Fu­ru­vik Zoo in Swe­den, where he was moved at age 5 af­ter hav­ing been born at the Mu­nich Zoo in West Ger­ma­ny in 1978. The stone-throw­ing ob­serv­a­tions be­gan in the late 1990s.

While re­search­ers have seen many ape be­hav­iors that could in­volve plan­ning, it gen­er­ally has­n’t been pos­si­ble to judge wheth­er they were really meet­ing a cur­rent or fu­ture need, Os­vath said.

For in­stance, when a chimp breaks a twig for ter­mite fish­ing or col­lects a stone for nut crack­ing, it can al­ways be ar­gued that they are mo­ti­vat­ed by im­me­di­ate rath­er than fu­ture cir­cum­stances.

And that’s what makes the newly de­scribed case so spe­cial, Os­vath said. It is clear that the chim­p’s plan­ning be­hav­ior is not based on a “cur­rent drive state.” In con­trast to the chim­p’s ex­treme agita­t­ion when throw­ing the stones, he was al­ways calm when col­lect­ing or ma­n­u­fac­tur­ing his am­mu­ni­tion. Zoo staff took extensive mea­sures to head off the as­saults by find­ing and clear­ing San­ti­no’s caches, Os­vath noted.

Os­vath said he thinks wild chimps in gen­er­al, as well as oth­er an­i­mals, pro­bab­ly have the plan­ning abil­ity San­ti­no dem­on­strat­ed. In­deed, ex­pe­ri­ments con­ducted re­cently with oth­er cap­tive chimps sug­gested they’re ca­pa­ble of mak­ing such plans, but some have ar­gued those find­ings may result from fac­tors parti­cular to the test set­up.

“I think that wild chim­pan­zees might be even bet­ter at plan­ning as they probably rely on it for their daily sur­vival,” Os­vath said. “The en­vi­ron­ment in a zoo is far less com­plex than in a for­est. Zoo chimps nev­er have to en­coun­ter the dan­gers in the for­est or live through per­i­ods of scarce food. Plan­ning would prove its val­ue in ‘real life’ much more than in a zoo.”

“The be­haviours al­so hint at a par­al­lel to hu­man ev­o­lu­tion, where si­m­i­lar forms of stone ma­nipula­t­ion con­sti­tute the most an­cient signs of cul­ture,” Os­vath wrote in the stu­dy. “Finds as old as 2.6 mil­lion years sug­gest that ho­minins [hu­man an­ces­tors] car­ried and ac­cu­mu­lat­e stone arte­facts on cer­tain sites, pre­sumably a case of fu­ture need plan­ning