SOURCE: University of Oxford, news release, July 28, 2015
FRIDAY, July 31, 2015 (HealthDay News) -- Chimpanzees in Uganda have started eating clay to supplement the minerals in their diet, researchers report.
The clay consumed by the chimps in the Budongo forest also helps them "detox" and digest their food, the study authors added.
The scientists observed wild chimps in the forest eating and drinking from clay pits and termite mounds. This change in diet may be partly due to the widespread destruction of raffia palm trees that the chimps typically relied on for their minerals.
"Raffia is a key source of sodium, but to our surprise the sodium content was very low in the diet so this does not appear to be the main reason for the new clay-bingeing," the study's lead author, Vernon Reynolds, emeritus professor of biological anthropology at University of Oxford in England, said in a university news release.
"Instead, the wide range of minerals present in their diet suggests that clay is eaten as a general mineral supplement," he added.
Findings from the study were published online July 28 in the journal PLoS One.
The study team observed the chimps using leaves like sponges. The chimps dipped the leaves in clay water and then squeezed the liquid out of the leaves with their tongues. They also used their fingers to take lumps of clay directly from the ground and then ate it.
An analysis of the clay showed it's high in a number of minerals, but particularly aluminium. The chimps' diet consists mainly of fruits and leaves and is high in tannins. The clay may provide a way for the chimps to neutralize the tannins, the researchers suggested.
The study authors noted that local women in Budongo often drink or eat forest clay mixed with water when they have stomach problems and during pregnancy.
Along with aluminium, the clay also contains sodium, calcium, iron, magnesium and potassium, according to the paper.
Look up the nutrient content of foods at the U.S. Department of Agriculture.