Melissa H Schmitt, Matthew S Rudolph, Sarah L Jacobson, Joshua M Plotnik

While African savanna and Asian elephants split between 4.2-9 MYA, they are often regarded as one united group, ‘elephants,’ even in the scientific literature. This is concerning, as while both are keystone species in their respective habitats, each face different environmental pressures and have rarely been compared experimentally. Savanna elephants must locate resources that vary spatially and temporally across patchy savannas, while Asian elephants do so within dense forests containing high biodiversity. Both species use olfaction to guide decision-making, however, considering their ecologies, we hypothesize that their olfactory abilities differ. Thus, we investigated the sensitivity and detection limits of both savanna and Asian elephants’ olfactory systems, as well as changes in these limits in a complex odour environment using two odour-based choice experiments. While both species correctly detected a target odour – savanna elephants detected it at 50 parts per million (ppm) and Asian elephants at 100 ppm – only the savanna elephants’ limit changed (to 1,000 ppm) in the complex odour environment. Our findings suggest that these species have similar olfactory sensitivity, which probably evolved in a shared ancestor, but divergent olfactory discrimination abilities, which are likely a result of variation in both the density and species diversity of their habitats.