One of the most universal rituals in human history is the eating of clay, with evidence of people doing it existing in almost every country known to have an ancient civilization with the possible exceptions of Japan and Korea.
Eating clay was referenced by the early physician Hippocrates, as well as the works of Pliny the Elder, and several countries have clay-eating practices that exist to this day, either as part of a clay detox or as part of regional delicacies.
Exactly how old the concept of eating clay is, however, has been difficult to quantify, but if evidence found at Kalambo Falls is anything to go by, the practice could perhaps be as ancient as humanity itself, if not more so.
Kalambo Falls on the border of Tanzania and Zambia is one of the most important archaeological sites in the world, as it contains some of the earliest evidence of human life even predating the development of homo sapiens.
In one of the dig sites at Kalambo Falls was the skeleton of a homo habilis (handyman), who was found surrounded by a white clay rich in calcium, which is possibly a form of bentonite.
What makes this find so fascinating is that homo habilis lived from around 2.31 million years ago to roughly 1.65 million years ago, which means that clay-eating predates human beings as they currently exist.
Given how old the find is, there is almost no way to identify why this ancestor of humanity ate bentonite. It could have been a source of food or a way to suppress appetite, it could have been a form of early detox or it could have just been for its own sake.
In any case, this only highlights how long and widespread consuming kaolin and other clays has been.