Geophagy is the behavior of consuming earth, clay, or soil-like materials. This behavior has been noted in many species including humans. My contribution to the Wikipedia page on Geophagy (http://en.wikipedia.org/wiki/Geophagy) included specific behaviors of geophagy in primates and bats.

Many hypotheses exist to explain the importance of geophagy in bats and primates^2,3. Some documented benefits of geophagy include nutrition, detoxification, and benefit as an antimicrobial and anti-parasitic agent; however, the reasons for geophagy are largely species specific^{1, 3}.

PRIMATES:

Krishnamani and Mahaney evaluated various hypotheses that could lead to maintained geophagy in different species of primates including Japanese macaques and chimpanzees². Reasons for geophagy are largely dependent on the species as well as the habitat. For instance, mountain gorillas demonstrate geophagy as a result of an increased need for iron.  Iron supplementation from the soil helps to meet the demands of decreased oxygen partial pressure at high altitudes².

BATS:

There has been great debate over whether geophagy in bats is primarily motivated by nutritional supplementation or by detoxification. It is known that some species of bats regularly visit mineral or salt licks to increase mineral consumption. However, Voigt et al. 2008 demonstrated that both mineral- deficient and healthy bats visit salt licks at the same rate³. Therefore, it would seem that mineral supplementation is not the primary reason for geophagy in bats. Additionally, it was found that bat occurrence at salt licks increased during periods of high energy demand. Voigt et al. 2008 concluded that the primary purpose for bat presence at salt licks is for detoxification purposes, compensating for the increased consumption of toxic fruit and seeds³. This was shown to be especially evident in lactating and pregnant bats as their food intake increases to meet higher energy demands³. (more…)