Tracing the Source of the Elephant And Hippopotamus Ivory from ...

The two hallmark articles illustrating the success of using isotopes to source ivory
are van der Merwe et al. (1990) and Vogel et al. (1990). As Price et al. (2002: 122)
pointed out, the homogeneity of the isotopic signatures (with a very low standard
deviation and coefficient of variation) despite potentially heterogeneous geological
sources and seasonal variation in diet is encouraging for sourcing ivory. Van der Merwe
et al. (1990) sampled bone and ivory from 100 elephants in 20 game refuges in 10
African countries and found seasonal variation in diet and seasonal migration most
pronounced in desert regions (i.e. Northern Namibia). Elephant populations from areas
situated on old granitic rocks (shield areas) have ratios >0.715, while populations from
basaltic regions have