Schmitt Melissa H, Rudolph Matthew S, Jacobson Sarah L, Plotnik Joshua M
Department of Biology University of North Dakota Grand Forks North Dakota USA.
School of Biology and Environmental Sciences University of Mpumalanga Nelspruit South Africa.
Ecol Evol. 2025 Aug 11;15(8):e71896. doi: 10.1002/ece3.71896. eCollection 2025 Aug.
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 -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., = 5 for each species), our data suggest that there may be differences in the olfactory abilities of these two elephant species.
虽然非洲草原象和亚洲象在420万至900万年前就已分化，但它们通常被视为一个统一的群体——“大象”。这很令人惊讶，因为尽管它们在各自的栖息地都是关键物种，但面临着不同的环境压力，而且很少进行实验比较。一般来说，非洲草原象必须在零散的草原上寻找时空上分布各异的资源，而亚洲象则要在茂密、生物多样性高的森林中寻找资源。这两个物种都利用嗅觉来指导决策；然而，考虑到它们的生态环境，我们推测它们的嗅觉能力有所不同。因此，我们研究了草原象和亚洲象嗅觉系统的敏感度极限和辨别能力，以及在复杂气味环境中这些极限的变化。我们采用了两项基于气味的选择实验，使用一种全球植物都会释放的常见绿叶挥发物作为目标气味。虽然两个物种都能正确检测到目标气味，尽管浓度不同——草原象在百万分之50（ppm）时能检测到，亚洲象在百万分之100时能检测到——但只有草原象在复杂气味环境中的极限发生了变化（变为百万分之1000）。尽管我们受到样本量小的限制（即每个物种只有5头），但我们的数据表明这两种象的嗅觉能力可能存在差异。
