Bonobos won't eat filthy food, offering clues to the origins of disgust

June 4 (UPI) -- Bonobos won't eat dirty food. In experiments, the great apes refused fruit that had been contaminated by feces.

Scientists wanted to better understand the evolutionary origins of disgust. The reaction helps humans avoid exposure to pathogens, and the latest research suggests the reaction offers apes' similar benefits.

Researchers at Kyoto University in Japan offered bonobos several food options: clean apple slices and apple slices tainted by either feces or dirt. Scientists also offered the apes banana slices positioned at various distances from fresh feces.

The bonobos most avoided contaminated apples, opting for the clean slices, and were more likely to eat banana slices placed farther away from sources of pathogens. Tests showed the bonobos were also less likely to have an appetite when served their meals alongside healthy whiffs of rotting meat.

Researchers found the apes "reduced tactile, gustatory and tool use activities" when exposed to foul smells, suggesting the apes use sight and smell to assess risk when considering the potential for exposure to pathogens in various feeding situations.

The results of the experiments were published Monday in the journal Philosophical Transactions of the Royal Society B.

"The team now plans to test whether bonobos confronted with contaminated food show the same facial expressions that humans do in similar situations," according to the journal Nature.