Chimpanzees remember the exact location of all their favourite fruit trees. Their spatial memory is so precise that they can find a single tree among more than 12,000 others within a patch of forest, primatologists have found….Acquiring such an ability may have helped drive the evolution of sophisticated primate brains.
Emmanuelle Normand and Christophe Boesch of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany teamed up with Simone Ban of the University of Cocody in Abidjan, Cote d'Ivoire to investigate the spatial memory of chimpanzees in the wild.
"We were amazed by the apparent easiness by which chimpanzees discover highly productive fruit trees. Or how after being separated from other group members for hours or days, they could join each other silently at a large fruit tree, like if they would have had an appointment at this place," says Normand.
Remarkably, as well as remembering the location of their favourite trees, the chimps also recalled when each tree would be in season, producing the most fruit. They would then often walk further to reach these more bountiful trees rather than make a shorter journey to a less productive one.
I can relate to this. I still remember the exact location and appearance of fruit trees I ate from decades ago. Is that my chimp brain at work? Apparently so:
In one respect, it is not surprising that chimpanzees have developed an
outstanding ability to navigate their home range, says Normand.
One idea, known as the 'ecological hypothesis' proposes that the need to remember
and find food resources, such as fruit trees, could have driven the evolution of
primate brains. In particular, it says that a preference for fruit eating, or frugivory, would select for intelligence compared to leaf-eating, or foliovory.
"That's because the distribution of fruits is more scattered, less predictable and fruits can be more difficult to manipulate than leaves, the nut cracking by Ta chimpanzees being an extreme example," says Normand.
Compared to monkeys, chimpanzees live in larger territories and are highly frugivorous, suggesting that developing an outstanding ability to navigate to fruit trees could have a key driver in the evolution of ape intelligence.
Frugivory! What a word! Maybe I’ll have to change the name of this blog.
And it sure is nice to know that eating fruit made us all smarter.
Source:
Chimps mentally map fruit trees, by Matt Walker
http://news.bbc.co.uk/earth/hi/earth_news/newsid_8086000/8086246.stm
