THE TWO PERCEPTUAL WORLDS OF AMPHIBIOUS FISHES: THE SENSORY ECOLOGY OF PERIOPHTHALMUS BARBARUS

Abstract

The evolutionary transition of vertebrates from water to land required extensive modifications to sensory systems originally adapted for aquatic environments, enabling them to function effectively in terrestrial settings. Mudskippers (Oxudercidae), amphibious fishes that live in both aquatic and terrestrial habitats, serve as a powerful model for investigating how animals manage two distinct sensory worlds. This study tested whether mudskippers experience separate sensory experiences in water and on land by measuring visual and olfactory acuity in each environment. Visual acuity was assessed using an optomotor assay, and olfactory sensitivity was measured by recording electro-olfactogram (EOG) responses to a panel of odorants. Results show that mudskippers have significantly higher visual acuity in air than in water, supporting prior predictions based on morphological adaptations for aerial vision. In contrast, olfactory responses were markedly stronger and more diverse in water. Together, these findings demonstrate that mudskippers possess distinct sensory capacities in air and water, supporting the hypothesis that they perceive land and sea through different senses. These results highlight the importance of sensory tradeoffs during the water-to-land transition and call for further research into the mechanisms underlying multimodal sensory adaptation in amphibious species.