Sounds produced by the tucuxi (Sotalia fluviatilis) from the Napo and Aguarico rivers of Ecuador

Abstract

The acoustic structure and repertoire of the tucuxi (Sotalia fluviatilis) remain poorly studied. This lack of information limits our understanding of how acoustic signals evolved and the factors that promote variation across and within populations. Using a broadband recording system, we recorded 30 whistles from tucuxis in the Napo and Aguarico Rivers, Ecuador. Our results show that Ecuadorian tucuxis emit a variety of sounds including whistles, echolocation clicks, and pulse sounds. Whistles structure varied with respect to other populations described in previous studies, providing preliminary evidence of geographic variation. In addition, this study provides evidence of high order harmonics in whistles (up to 80kHz) highlighting the importance of broadband recording systems.