London, June 9 (ANI): Chimpanzees have an inherent spatial memory that makes them remember the exact location of all their favourite fruit trees, according to a study.
In fact, primatologists have found that their spatial memory is so precise that they can find a single tree among more than 12,000 others within a patch of forest.
Moreover, the chimps also recall how productive each tree is, and decide to travel further to eat from those they know will yield the most fruit.
The scientists have suggested that acquiring such an ability may have helped drive the evolution of sophisticated primate brains.
Led by Emmanuelle Normand and Christophe Boesch of the Max Planck Institute for Evolutionary Anthropology in Leipzig, the study was aimed 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," the BBC quoted Normand as saying.
For the study, firstly the researchers mapped the location of 12,499 individual trees growing within the home range of a group of chimpanzees living in the Tai National Park in the Cote d'Ivoire.
They identified each tree and used GPS to map its precise position.
The researchers also identified 17 species of fruit tree that the chimps regularly fed from, and worked out how often each individual tree belonging to those 17 species would be in fruit each month.
The data enabled the researcher to determine how likely it would be that a chimp randomly walking around the forest might come across a fruit tree that it could feed from.
It was found that the chimps didn't visit the most abundant fruit species most frequently. Instead, they targeted certain trees and walked directly to them.
Also, they travelled much shorter distances to each fruit tree than would be expected by chance, which confirmed that they travel directly to the trees.
"We think it is fair to assume that chimpanzees can remember the exact location of probably thousands of trees," said Normand.
Surprisingly, other than 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.
"Across all seasons, it seems that they have preferred tree species," said Normand.
The study has been published in Animal Cognition. (ANI)