Aerial urination in Amazon river dolphins: reassessing its social significance and implications for sensory biology

Araújo-Wang et al. (2025) reported on aerial urination events in male Amazon river dolphins (Inia araguaiaensis) from the Tocantins River in Brazil, a phenomenon that appears to occur across populations of Inia. The authors argue that this behavior would be indicative of a yet undescribed sensory modality in these animals and that it probably represents an intrasexual display of dominance. However, both of these claims do not appear plausible in light of the limited available data. If indeed functional, aerial urination is more parsimoniously explained as a form of solo or social play.