Fruit-Loving Lemurs Have Better Memory

Researchers have found that a fruit-heavy diet improves the lemur's memory, including remembering exactly where it found the food.

A team at Duke University conducted the study, which tested to see how diet affected spatial memory for lemurs, Science Recorder reported via a Duke press release.

The research provided backing for a theory that a less varied diet relying on more difficult to find foods gives some lemurs a competitive advantage.

Alexandra Rosati from Yale University and Kerri Rodriguez and Brian Hare of Duke worked with five species of lemurs living in captivity at the Duke Lemur Center and reported their findings in the journal Animal Cognition, according to the press release.

Working with a total of 64 lemurs, the researchers compared spatial memory skills for "fruit-eating red-ruffed and black-and-white ruffed lemurs, leaf-eating Coquerel's sifakas, and ring-tailed and mongoose lemurs that eat a mix of fruit, leaves, seeds, flowers, nectar and insects," said the press release.

Ruffed lemurs living in their native Madagascar consume a diet that is 90 percent fruit and especially relies on figs.

The animals were tested in a T-shaped maze where food was hidden in one of the maze's two arms. The lemurs that heavily rely on fruit for their diet were the only ones able to remember the spot a week afterward.

The researchers also tested whether the lemurs remembered the actual location of the food or just the turns they took to find it. They let the lemurs discover where food was in the maze and then moved the animals 10 minutes later to a new starting place.

"Before they might have turned right, but now they had to turn left to get to the same spot," Rosati explained in the press release.

Even when different turns were required, the fruit-loving ruffed lemurs were the mostly likely to find the right spot again.

The ruffed lemurs also excelled at another experiment where the researchers placed food in half of eight open boxes and let the animals search for the treats. All of the boxes had distinct visual markings.

For the second half of that experiment, the team placed food in all of the boxes and covered them. The ruffed lemurs were the only ones to head toward the containers that had earlier held food.

Their memory helps them survive in the wild since foraging for fruit can be difficult depending on the season. While ring-tailed and mongoose lemurs can find their food just about any time, the ruffed lemurs need keen spatial memory and recall to find fruit from one season to the next.