Stable Isotope Analyses of Carbon and Nitrogen in Hair Keratin of Suspected Man-Eating Wolves from the 1880s

The study used stable isotope analyses of carbon and nitrogen in hair keratin to investigate the diet of wolves from the 1880s in Finland, suspected of killing 22 children. The nitrogen stable isotope values in the wolves' hair keratin were found to be the lowest compared to reference samples, indicating a diet with less protein from higher trophic positions, contrary to the expected results if human flesh was a significant part of their diet. The wolves' diet was found to align with herbivorous and omnivorous animal species from a terrestrial C3 plant-based community, including domestic animals. The study suggests that the significant reduction of the moose population, the main prey of wolves, in the late nineteenth century may have led some wolves to rely on atypical nutrition, including potentially human tissue. However, human tissue likely covered less than a tenth of what was nutritionally required by the wolf pack and thus could not significantly affect the isotopic values. The study also found isotopic signs of some aquatic species in the wolves' diet. The study faced limitations in estimating the amount of human biomass consumed by the wolves and in the unsuccessful analysis of bone collagen stable isotope results.