Researchers from the Zoological Society of London set up puzzle tests for six chimpanzees at the society's Whipsnade Zoo that involved the primates using sticks to move red dice through a maze of pipes until they fall into an exit chamber.
Then the same puzzles were presented using Brazil nuts instead of dice that would fall not into a chamber but out of the puzzle as a tasty treat for the chimps.
"We noticed that the chimps were keen to complete the puzzle regardless of whether or not they received a food reward," zoological society researcher Fay Clark said. "This strongly suggests they get similar feelings of satisfaction to humans who often complete brain games for a feel-good reward."
The chimpanzees were not trained on how to use the device and doing the brain teaser was completely voluntary for the animals , she said.
"For chimps in the wild, this task is a little bit like foraging for insects or honey inside a tree stump or a termite mound; except more challenging because the dice do not stick to the tool," Fay said in a society release.
The researchers said the study suggests that like humans, chimpanzees are motivated to solve a puzzle even when there is no immediate reward, for the sake of the challenge itself.