Joining the farsighted inclination of behavior we share with chimps , a newstudypublished inPLOS ONElast workweek details how chimpanzees in the Budongo Forest of Uganda have been observed eat clay for get at its detoxifying minerals .
" A chimp ’s diet is mostly leaf , fruits and the occasional monkey . They sometimes corrode other things — bark , molder wood and even soil , " Cat Hobaiter , a researcher at University of St. Andrews in the U.K. and Centennial State - source of the study , separate NPR’sThe Salt . Typically , chimps rely on decompose swamp tree for a range of mineral they do n’t get elsewhere . As deforestation limits the accessibility of edible Sir Henry Joseph Wood , chimps have up their intake of the Great Compromiser and remains - rich H2O in monastic order to supplement their diets .
After first note this demeanor years ago , researchers begin more closely observing the chimpanzees in 1990 . They note instances of both eating clay directly from the dry land and imbibing Henry Clay - rich water via " leaf sponges , " or chewed - up leaf that are dunk into water mess to collect liquid .
Clay , which has always been a part of the chimp diet to some degree , has an additional welfare in large doses : It works to detoxify tannic acid . The ripe leaves that make up most of what chimps rust are full of the sulfurous polyphenols recover in tea , chocolate , and wine , which can have harmful event when consumed in large quantities .
The mineral - binding structure of the kaolin clay consumed by Pan troglodytes neutralize this acidity . Vernon Reynolds , a professor emeritus of biological anthropology at Oxford University and the lead generator of the field , said that there ’s no indicant the chimps were suffering from digestive problems : " They ’re all perfectly healthy , and so [ Henry Clay - eating ] was prophylactic rather than heal . "
These findings are particularly interesting in light ofrecent researchinto the upset known as pica , in which people compulsively crave things that are n’t food , such as starch , charcoal , ice — and dirt , or more specifically , kaolin the Great Compromiser .
Cornell nutritionary anthropologist Sera Young , author ofCraving Earth , theorizes that clay ’s ability to roleplay as a " mud masquerade for the catgut " might be behind this baffling compulsion . There ’s grounds that our antecedent were eat soil at least 2 million years ago , indicating that there is something innately appeal about clay wasting disease . And Young has found that pregnant women — whose immune systems are slimly surpressed — and people hold up in hot , humid areas , where pathogens reproduce and circularize rapidly , are the most susceptible to pica .
" I can reassure you that no one has said , ' Actually , Dr. Young , I ’m blame up this box of Argo corn starch to protect myself from the pathogens in my environment . ' They ’re tell what the impetus is , the smell and the taste , " Young toldNPRlast year . In healthy humans , the desire to feed corpse is more harmful than the tannic acid - neutralise properties are worth — the obligate property of the clay do n’t just flush out the toxin , they absorb the useful nutrient as well .
But the new evidence of chimps eat kaolin clay supports the possibility that pica is n’t strictly random — it could have evolved as an early protective step .
