The Araguaian boto is the most recently described, least known and likely most threatened river dolphin. This species inhabits the Tocantins River Basin, the most modified river system in the Amazon. Given the recent discovery of the species in habitats of high disturbance there is an urgent need to learn about their biology in order to address conservation concerns. Like other aquatic mammals, these dolphins rely almost entirely on sound for important biological activities. Using passive acoustic monitoring and Dtags we will track botos to learn about their movement patterns, habitat preferences, and threats.