Chimpanzees in Uganda’s Budongo Forest have added a new foodstuff to their menu: clay. And they aren’t just taking dainty bites; they’re bingeing, say researchers who report on the novel behavior this week in PLOS ONE. Whereas the chimps in the nearby Kibale Forest regularly consume a mixture of soil and leaves (apparently for the high iron content), the Budongo apes, which scientists have studied since 1990, don’t. These chimps did, however, feed on the decaying pith of Raffia palm trees, which is a good source of minerals. But since 2005, due to widespread destruction of the palms, the apes have largely lost this nutritional source. Instead, they’ve turned to eating and drinking clay from clay pits and termite mounds. Some of the chimps dip leaves into the water in the pits and suck out the clay-soaked liquid. Others use their fingers to dig up lumps of clay, which they then eat (as in the video above). The chimps’ primary diet, which consists largely of fruits and leaves, is high in tannins. The clay, which contains aluminum and other minerals, may help the animals neutralize and digest the tannins. If so, they’ve discovered something that the local Budongo women know as well: When these ladies have an upset stomach, they cure it by eating or drinking forest clay mixed with water.
(Video credit: Brittany Fallon)