Journal Article

Differences in Olfactory Discrimination, but Not Sensitivity, Between African Savanna and Asian Elephants

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

2025

Overview

While African savanna and Asian elephants split between 4.2 and 9 MYA, they are often regarded as one united group, ‘elephants.’ This is surprising because, while both are keystone species in their respective habitats, each faces different environmental pressures and has rarely been compared experimentally. In general, African savanna elephants must locate resources that vary spatially and temporally across patchy savannas, while Asian elephants do so within dense, high‐biodiversity forests. Both species use olfaction to guide decision‐making; however, considering their ecologies, we hypothesize that their olfactory abilities differ. Thus, we investigated the sensitivity limits and discrimination abilities of both savanna and Asian elephants' olfactory systems, and changes in these limits in a complex odor environment. We employed two odor‐based choice experiments, using cis‐3‐Hexenyl acetate—a common green leaf volatile that is emitted by plants globally—as a target odor. While both species correctly detected a target odor, albeit at different concentrations—savanna elephants detected it at 50 parts per million (ppm) and Asian elephants at 100 ppm—only the savanna elephants' limit changed (to 1000 ppm) in the complex odor environment. While we were limited by a small sample size (i.e., n = 5 for each species), our data suggest that there may be differences in the olfactory abilities of these two elephant species. While African savanna and Asian elephants split between 4.2 and 9 MYA, they are often regarded as one united group, ‘elephants,’ even in the scientific literature. This is surprising, because while both are keystone species in their respective habitats, each faces different environmental pressures and has rarely been compared experimentally. Thus, we investigated the sensitivity and detection limits of both savanna and Asian elephants' olfactory systems, and changes in these limits in a complex odor environment using two odor‐based choice experiments. While both species correctly detected a target odor—savanna elephants detected it at 50 parts per million (ppm) and Asian elephants at 100 ppm—only the savanna elephants' limit changed (to 1000 ppm) in the complex odor environment. While we were limited by a small sample size, our data suggest that there may be differences in how these two species of elephants detect odors.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc,Wiley
• Subject: Acetic acid / Biodiversity / cognition / Decision making / Elephants / evolutionary ecology / Experiments / Flowers & plants / Food / Food quality / Foraging behavior / foraging ecology / Forests / Grasses / Habitats / Keystone species / Monkeys & apes / Odors / Olfaction / Olfactory discrimination / Olfactory discrimination learning / Savannahs / Sensitivity / sensory abilities / Target detection / Vegetation / VOCs / Volatile organic compounds