Researchers studying dozens of wild chimpanzee residential area have recorded many of the apes do it and hurl rocks against trees , produce blatant assemblage of stones . The finding , published inScientific Reportsthis week , describe the first repeated observations of individual chimps using stone tools for a intention other than extractive forage .
Second to humans , chimp ( Pan recluse ) exhibit the greatest variant in tool - use behaviors . They use leaves , sticks , and twigs to develop food , Harlan F. Stone hammer and anvils to crack up assailable nuts , and I. F. Stone meat cleaver to cut up large fruits . But what we know about their tool - use repertory is limited to a patchy distribution of long - term field sites .
To aid get the best this restriction , a huge international team lead byAmmie Kalanfrom the Max Planck Institute for Evolutionary Anthropology learn a total of 34 Pan troglodytes communities across the species ’ range as part of the Pan African Programme : The Cultured Chimpanzee ( PanAf ) . Data collection at each PanAf website is conducted for periods lasting 14 to 17 calendar month . The team also see published data from 17 mid- to long - term chimpanzee research internet site .
Field workers first hear gem banging in 2010 at Boé , Guinea - Bissau , and the first confirm reflection of accumulative Harlan Stone throwing occur in 2011 at Sangaredi , Guinea , after special markings were discovered on a hollow tree . The team then strapped remote video camera trap on Tree near locating where signal of stone throwing or piling behavior were find . When reviewing the videos , they sort out stone - throw behavior found on the type of handling observed : bang , hurl , or toss . hurtle means they used one or both hands to throw a stone at the tree , while tossing means they flip the rock into a core out - out tree or a hollow groove formed by buttress root .
The researchers find that chimpanzee from four populations in West Africa – Guinea - Bissau , Guinea , Liberia , and Côte d’Ivoire – habitually know and confound rocks against trees or tossed them into tree cavities . These behaviors result in blatant signs of wear and stone accumulations contain up to 37 rocks . The squad recorded a sum of 64 stone throwing events : Either the chimps held a Harlan Stone in their hands or they had grabbed one , then threw it .
These ceramicist were mostly adult males , and in almost all of the instance , gemstone throwing was company by what ’s called the “ pant hoot , ” part of a ritualized aggressive display that also involves swot with the hands and foot . It ’s possible that the battering could be a adjustment of the male exhibit that raise healthy propagation .
Or perhaps the Edward Durell Stone piles help mark territory boundaries . researcher studying the remains of our extinct ancestors often trust on comparisons with living order Primates to assist shed light on prehistoric behaviour . pit throwing and the accumulation that result are redolent of human cairn . Ancient and modern human society used gemstone piles to pit intellectual nourishment caches or pathways . Some of these sites might also hold a more symbolic substance for burials or to help establish shrines .
