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

Figure 39: “Carbon and nitrogen isotope map of African elephant populations. Boxes
map mean ± 1 SD for each population; circles refer to single specimens. There is
significant overlap between the Amboseli population and several other populations,
especially when total range is plotted for Amboseli. Data for all populations except that
of Amboseli were compiled from the literature [van der Merwe et al. 1990; Vogel et al.
1990]” (Koch et al. 1995: 1342).
likely to exhibit intra-tusk variability. Moreover, because carbon and nitrogen isotope
values may be the same in geographically separated populations (see Figure 39 for
illustration of this problem), sourcing ivory should rely heavily on those geological
isotopes (Sr, Nd, and Pb) as suggested above.
Ishibashi et al. (1999) conducted one of the largest research programs on
elephants utilizing isotopic analysis: eighty-one samples (collagen) from eleven
countries, including some countries previously included in isotopic studies (Sudan,
Djibouti, and Ethiopia). The results of their research are listed in Table 6 by country.
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