Pteronura brasiliensis is a piscivore. It hunts during the day, usually along river and lake margins. Hunting is done primarily by vision, but hearing, smell and touch are also well suited for murky water. Fish are captured in solitary or social hunts. Shallow water hunts take place along water edges where fish hide among vegetation. These hunts are solitary and more successful in terms of fish per individual. Deep water hunts are performed by families. Synchronous dives and organized trapping of prey against shorelines are sometimes observed.
The preferred fish diet of P. brasiliensis includes members of the catfish, perch and characin families. When fish abundance is low, P. brasiliensis feeds on crustacenas, small snakes and small caiman. Food is either taken to shore (large prey) or eaten while P. brasiliensis floats on its back (small prey). Pteronura brasiliensis takes in about 6-9 pounds of seafood per day.
Carter and Rosas (1997), Eisenberg (1989), Emmons (1990), Laidler (1982), Nowak (1991)