It is the Spanishization of a technical term in Zoology and Ornithology (of the genus Anhinga), to which belongs the Needle Duck or Cotúa. Familiarization and frequent use has forced it to take it as another common name of the species. The word is of Tupi-Guarani origin and means small head. It was also the name of an evil spirit in its mythology of a being half bird and half snake, very similar to the appearance of the needle duck (some call it snake duck).
