Five lemur species fed a fruit-rich diet were found to have better spatial memory than those fed a more varied diet, according to a study published in the journal Animal Cognition.

The study conducted by researchers from Duke and Yale universities included red-ruffed and black-and-white ruffed lemurs, Coquerel's sifakas, and ring-tailed and mongoose lemurs, reported Phsy.org. The species eat a combination of fruit, leaves, seeds, flowers, nectar and insects.

While Coquerel's sifakas eat mostly leaves, ruffed lemurs can have a diet of up to 90% fruit, mostly figs, in their native habitat in Madagascar.

The study evaluated 64 animals on their ability to remember the location food placed in mazes and in boxes. In the first experiment, lemurs were led to food hidden in a maze and returned a week later to test their retention of the location.

In a second, more difficult challenge, the lemurs were placed in a different location of the maze, to see if they simply remembered the route or if they actually recalled the location of the food. Again, the fruit-eating lemurs were most likely to find the food.

In an additional test, the lemurs were presented with eight boxes with distinct visual clues, half of which contained food. Later, all eight were filled with food and covered.

Upon return, only the ruffed lemurs preferred the boxes that had previously contained food, reported Phsy.org.

The findings indicate the importance of lemur memory in locating food sources in their natural habitat.

It also corresponds with the demands placed on the species in their natural habitat. Given the seasonal availability of fruit, ruffed lemurs must remember when and where keys foods are available. Coquerel's sifakas, which each mostly leaves, have a much easier task when it comes to finding suitable food sources.

Photo: Black and white-ruffed lemur in South Africa, by Charlesjsharp via Wikimedia Commons

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