Abstract:
Geophagy or deliberate ingestion of soils has been observed among Asian elephants (Elephas
maximus) in the Udawalwe National Park, Sri Lanka, for several years. The geochemical and
mineralogical composition of the clayey soil layers which are purposefully selected and eaten by
elephants in the park were studied, in order to identify the possible reasons for elephant
geophagy. The concentrations of major and trace elements were determined by means of X-ray
fluorescence spectrometry in 21 soil samples from eight geophagic sites and six soil samples
collectedfrom four non-geophagic sites. The mineralogical composition of selected soil samples
wasinvestigated using X-ray diffractometry (XRD). The geochemical analyses revealed that the
geophagic soils in the study areas are deeply weathered and most of the trace elements are
leachedfrom the soil layers under extreme, weathering conditions. The XRD data shows that the
soilsof the area consisted mainly quartz, feldspar, and the clay minerals mainly kaolinite, Fe-rich
illite, and smectite. Although no significant geochemical differences were identified between
geophagic and non-geophagic soils, a clear difference was observed in their clay mineralogical
content. Soils eaten by elephants are richer in kaolinite and illite than non-geophagic soils,
whichcontain a higher amount of smectite. It is suggested that elephants in Udawalawe National
Park ingest soils mainly not to supplement the mineral contents of their forage but to detoxify
unpalatablecompounds in their diet.
