Tsavo Man-Eaters - Modern Research

Modern Research

The two lion specimens in Chicago's Field Museum are known as FMNH 23970 (killed December 9, 1898) and FMNH 23969 (killed December 29, 1898). Recent studies have been made upon the isotopic signature analysis of Δ13C and Nitrogen-15 in their bone collagen and hair keratin and published in the Proceedings of the National Academy of Sciences USA. Using realistic assumptions on the consumable tissue per victim, lion energetic needs, and their assimilation efficiencies, researchers compared the man-eaters' Δ13C signatures to various reference standards: Tsavo lions with normal (wildlife) diets, grazers and browsers from Tsavo East and Tsavo West, and the skeletal remains of Taita people from the early 20th century. This analysis estimated that FMNH 23969 ate the equivalent of 10.5 humans and that FMNH 23970 ate 24.2 humans. This leads to the conclusion that the lower number of 35 victims is more likely and that Patterson exaggerated his claims (though this claim doesn't take into account the people that were killed, but not eaten by the animals). It also adds credence to the infirmity theory that the root-tip abscess on the lower right canine of FMNH 23970 (the first man-eater) triggered the man-eating episode.

However, an earlier (2001) study by Tom Gnoske and Julian Kerbis Peterhans, published in the Journal of the East African Natural History Society, contended that a human toll of 100 or more was possible. The diet of the victims would also affect their isotopic signature. A low meat diet would produce a signature more typical of herbivores in the victims, affecting the outcome of the test. This research also excludes, but does not disprove, the claims that the lions were not eating the victims they killed but merely killing just to be killing. Similar claims have been made of other wildlife predators.