I want to thank Amy for posting this article.
Chimpanzees in West Africa are throwing rocks at trees, and why they’re doing it remains a mystery, Discovery reports. Researchers from the Max Planck Institute for Evolutionary Anthropology say this chimp behavior has never before been documented and that it may shed some light on the species’ cultural customs—and even those of early humans.
The scientists involved in the study published in Scientific Reports note that with camera traps, they found four chimp populations that “habitually bang and throw rocks against trees, or toss them into tree cavities,” amassing the rocks in “conspicuous” piles.
The chimps are seen on camera picking up stones, then lobbing them at the trees while letting out a “long-distance pant hoot vocalization.” It’s been mostly males observed engaging in this behavior (and only in West Africa), though there have been some females and juvenile chimps that have also taken part.
And while chimps are known to use various tools for foraging—a press release notes they’ll wield sticks to get bugs or honey, or stone or wooden hammers to smash open nuts—that doesn’t seem to be the case here.
“As the stone accumulation behavior does not seem to be linked to either the abundance of stones or the availability of suitable trees in an area, it is likely that it has some cultural elements,” study co-author Christophe Boesch says.
Another co-author, Laura Kehoe, lists some possibilities for the Conversation: The loud behavior could be a (mostly) male display of some sort, or the rocks could be used as a “signpost” to mark paths or territories.
Or, Kehoe notes, they may be part of a “sacred” ritual. “Indigenous West African people have stone collections at ‘sacred’ trees and such man-made stone collections are commonly observed across the world and look eerily similar to what we have discovered here,” she writes.
Steven B
It is SOOOOOOOOOOOOOOOO easy to explain:
Chimp says to others: “Hey, here come them scientists again. Betchya I can make them scratch their heads. C’mon – throw some rocks at this tree over here. A-HAHAHAHAHA!!! Look at them. No wonder they’re hairless! Their behavior always baffles me.”
Laurie B
Target practice. Pure and simple.
Christopher c
Laurie B.I agree 100% !
Elise B
A contest? Just for fun? Same reason we throw horseshoes at pegs in the ground.
DonRay
Thats right Laurie,,, they’re gettin ready to take over……
diana m
Tree is hainted.
James M
WOULDN’T IT BE CREEPY IF THIS WAS SOME SORT OF EARLY RELIGION ?
Daniel S
I still do that my self
Irene A
http://www.dailymail.co.uk/sciencetech/article-3475816/Is-proof-chimps-believe-God-Scientists-baffled-footage-primates-throwing-rocks-building-shrines-sacred-tree-no-reason.html
Robin B
Hmmmmmmm, Irene A, good article! Thank you
Melanie W
Saw this article too… Amy beat me to it. Not sure I agree with the “religion” thing… but definitely a fascinating behavior which rings true with all the reports of the “American” ape rock throwing.
I for one will refrain from supposing I have any idea what goes on in another species mind.