I first read about animals eating clay in an article by Linda Clark, author of Get Well Naturally, who mentioned that elk, deer, coyote, and lynx gather in certain areas that contained clay.

 Animals are instinctively drawn to clay, she said, often when it is in the form of mud. The animals lick the clay or, if injured, roll around in it to obtain relief from their injuries. Later, I learned more about other creatures who also depend upon clay as an important part of their everyday diet.

 Today it is clear that geophagy (the scientific word for the consumption of clay) is even more widespread in the animal kingdom than previously thought!

 What other Animals?

It has been reported in many species of birds; many species of herbivores (antelopes, elk, bison, elephants, and the like); and many species of omnivores (porcupines, bears, rats, gorillas, and chimpanzees). But no strict carnivores, interestingly, have been reported eating dirt.

As I wrote the chapter on animals eating clay, on my desk sat a research paper that reported about 50 different observations involving primates who eat clay. It detailed the species of primate, years of observation, location, and so forth.

What one can clearly see from this report is that this practice is neither isolated nor a one-time-only consumption. Primates who regularly consume clay are from all areas of the world—from countries in Africa to Brazil, China, Columbia, India, Indonesia, Madagascar, Peru, Thailand, and Venezuela. It was not country or region-specific behavior.

But Why Do They Eat Clay?

Perhaps even more fascinating is that the authors categorize the primates according to the hypothesis behind why they consume soil. What is it about those yummy-tasting volcanic soils that keep these animals going back for seconds?

 You may not be all that surprised to learn that the reasons why animals eat clay are very similar to why humans choose to pop a spoonful of dirt into their mouth.

 The main reasons for consumption are:

• Mineral supplementation

• Adjustment of gut pH and antacid action

• Adsorption of toxins

• And its use as an antidiarrheal agent