LONDON, Feb. 25 (UPI) -- Chimpanzees get a feeling of satisfaction from figuring out tricky puzzles whether they get a food reward or not, British researchers say.
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.