LE3 .A278 2010

2010

Shutler, Dave

Acadia University

Bachelor of Science

Honours

Environmental Science

Earth & Environmental Sciences

Geophagy, the intentional ingestion of soil, has been reported among many herbivorous and omnivorous animals, including humans. Tropical environments such as the Amazon rainforest have an abundance of bird and mammal species that are geophagous. Soil leaching is common in tropical environments and this can cause low nutrient levels in plant tissues. In addition, many plants use toxins to discourage consumption of their tissues or unripe fruit. Thus, two hypotheses for geophagy are ( i) for mineral supplementation, and ( ii) for detoxification of plant secondary compounds. These hypotheses may not be mutually exclusive. To test these hypotheses, soil samples were collected in the Peruvian Amazon from 13 clay lick sites ( licks) visited by a variety of birds and mammals along Rio de Madre de Dios and its tributaries. Non- lick samples were collected from similar sites not visited by these animals. Samples were analyzed for texture, composition, and exchangeable cation concentrations. The majority of the licks were clay- rich, a feature consistent with the detoxification hypothesis. Soil conductivity was higher in licks than in non- licks, as were exchangeable sodium concentrations and pH. This is consistent with the hypothesis that clay lick soils are less leached, and thus contain more nutrients. Thus, data from this study supported both the mineral supplementation and detoxification hypotheses for geophagy.

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https://scholar.acadiau.ca/islandora/object/theses:748