Chimpanzee Culture Demonstrated In Nut-Cracking Technique Study

This young chimp is using a stone to crack open a coula nut.

By Jennifer Welsh, LiveScience Staff Writer:

Like humans who might use a different slang term for "that's cool" or have distinct fashion sense, adjacent chimpanzee groups also show cultural differences, in this case, in their nut-cracking techniques, researchers have found.

"In humans, cultural differences are an essential part of what distinguishes neighboring groups that live in very similar environments," study researcher Lydia Luncz, of the Max Planck Institute for Evolutionary Anthropology in Germany, said in a statement.

"For the first time, a very similar situation has been found in wild chimpanzees living in the Taï National Park, Côte d'Ivoire, demonstrating that they share with us the ability for fine-scale cultural differentiation."

The researchers studied 45 chimpanzees from three different groups for the 2008, 2009 and 2010 nut-cracking seasons, as they use tools to open coula nuts from a tropical African tree of the same name. The chimps use hard "nutcrackers," which they craft from materials they find in their environment, to break the skin of these nuts against tree root "anvils." The nuts are hard at the beginning of the season, becoming softer and easier to crack open over time. [10 Animals That Use Tools]

Each of the three groups of chimpanzees in the national park ranges across about 1.5 square miles (4 square kilometers) of land, sharing a border with one of the other groups.

One of the groups used mostly nutcrackers made of stone to extract the meat from coula nuts, no matter how soft the nuts were. The other two groups started using wooden tools (which are easier to come by) to break open the nuts later in the season, using the stone tools only for the harder early-season nuts. All three communities had a special preference for how big of a hammer they used.

Interestingly, the chimpanzees from separate tribes are genetically the same, so they can and do interbreed between populations. In fact, the female chimpanzees of one group often move to mate with males from another group.

"We have documented differences in hammer choice within a single forest block, with members of three different adjacent chimpanzee communities that are in regular contact with one another and are thus not genetically differentiated," Luncz said.

Somehow, the females are able to adapt to their new culture's tool-use preferences; the researchers are currently studying these communities further to see how these females are able change the way they use tools.

"In many ways, chimpanzees are very similar to us humans," study researcher Christophe Boesch, also of the Max Planck Institute, said in a statement. "By studying the similarities to our closest living relatives in their natural habitat in Africa, we have the unique opportunity to learn more about the evolutionary roots of culture, which is for us humans one of the key elements of our identity."

The study was published today (May 10) in the journal Current Biology.

You can follow LiveScience staff writer Jennifer Welsh on Twitter, on Google+ or on Facebook. Follow LiveScience for the latest in science news and discoveries on Twitter and on Facebook.

• 8 Humanlike Behaviors of Primates
• Image Gallery: Our Closest Human Ancestor
• Gallery: Monkey Mug Shots

Copyright 2012 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Also on HuffPost:

From our partners

• Oklahoma Tornado Shows Progress In Weather Warnings - Climate Central
• Shopping Accounts For How Many Miles Traveled In U.S.? - Mother Nature Network
• Widespread Greenland Melting A Sign Of Things To Come - Climate Central

Comments

[servumtuum]

03:38 PM on 05/12/2012

It would be interesting to see if the newly discovered technique for cracking the coula nuts with pieces of wood after the nuts had softened was a more or less efficient method than using stones only. If it turns out to be more efficient-from the perspective of conferring a survival advantage then this could plausibly be characterized as an analog of one of the stages of the evolution of intelligence in homo sapiens rather than a cultural preference. If it turns out to be less efficient or equally efficient or, in other words does not enhance the probability of that group's survival relative to the "stones only" group then the cultural preference hypothesis may be in operation here. Basically what I'm saying that drawing the conclusion that this is a cultural artifact may be premature without more investigation.

[FTracy3]

04:28 PM on 05/11/2012

This is not breaking news to anyone who's ever watched just about any reality show on Bravo.

[chaya]

02:57 PM on 05/11/2012

"In many ways, chimpanzees are very similar to us humans."

Yeah. I'll agree with that when chimpanzees from the two different groups begin fighting to keep the other chimpanzees from being "different."

[evecaren]

08:31 AM on 05/11/2012

Chimpanzees are highly intelligent. Imagine having the foresight to use a rock as a tool
to open the coula nuts from the African tree of the same name. I find it fascinating that
one group of chimps use large stones to open the coula nuts. Apparently the other two groups use wooden tools which the article states are more easily available and when the
coula nuts are soft. All three chimp groups use large stones when the coula nuts are harder
to crack. I learned awhile ago that chimpanzees are the closest to humans in their DNA.

[sc00by]

05:36 PM on 05/10/2012

I thought Jane Goodall covered all this about 40 years ago. Yes, chimps are smart and have societies.