Wild Uganda Chimpanzees Using Clay as Food

http://www.nytimes.com/2015/08/04/science/wild-uganda-chimpanzees-using-clay-as-food.html

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Wild chimpanzees in Uganda have begun eating clay, which furnishes dietary minerals to them, a new study reports.

“I’d never seen this, and I’ve been observing them since 1962,” said Vernon Reynolds, a professor emeritus of biological anthropology at Oxford University and an author of the study, published in PLOS One. “Now, just recently, they’re really going for it in a big way.”

The researchers studied chimpanzees living in the Budongo Forest. Dr. Reynolds and his colleagues believe the chimps have turned to clay because of the widespread destruction of local raffia palm trees.

The chimpanzees used to eat the decayed pith of the tree, which contains minerals. The clay they have begun eating has “plenty of aluminum in it, high concentrations of iron, lots of manganese, magnesium and potassium,” Dr. Reynolds said. “It’s a cocktail of minerals.”

Raffia trees are being killed by local tobacco farmers, who strip the trees of leaves for use in curing and drying tobacco.

The chimpanzees also relied on raffia palm trees as a source of sodium, but the clay does not have high sodium levels, Dr. Reynolds said.

“We don’t know how they’ve replaced it,” he said. “But they are not short of salt, or else they’d show signs of deterioration.”