On the possible adaptive value of coprophagy in free-ranging chimpanzees.

Coprophagy occurred during major periods of feeding on fruits of Dialium spp. (Caesalpiniaceae) in a group of orphaned chimpanzees released in Conkouati Douli National Park, Republic of Congo. Since stress, boredom or food scarcity could not explain coprophagy according to our daily behavioral and veterinary control observations, we suggest that Dialium seeds were the item of interest in the feces. Two types of Dialium seeds were commonly found in the feces after chimpanzees swallowed the mesocarp and whole seeds together. These seeds were either whole and hard or whole/broken and soft imbibed. A mechanical and/or chemical effect of the gut passage may enable the chimpanzees to chew and ingest the seeds, thus providing nutritional intake.