«Manatee with calf.PD» de Gaylen Rathburn (Rathbun?) - USFWS Digital Library, WO3544-Highlights. Published by DIVISION OF PUBLIC AFFAIRS, U.S. Fish and Wildlife Service. Disponible bajo la licencia Dominio público vía Wikimedia Commons - https://commons.wikimedia.org/wiki/File:Manatee_with_calf.PD.jpg#/media/File:Manatee_with_calf.PD.jpg