• Height: 1.5 – 1.8 m
• Weight: 24 kg
• Best season: July – November
• Sightings: 40%

 Giant River Otter (Pteronura brasiliensis) is a large, semi-aquatic mammal found in the Amazon and Orinoco river basins. It has dark brown fur with a light throat, growing up to 1.8 meters long. Known for its social behavior, it lives in family groups and feeds primarily on fish, along with crustaceans and small reptiles. The otter plays a crucial role in regulating fish populations. Classified as Endangered, it faces threats from habitat loss, pollution, and hunting.

Giant river otter is not a very common mammal to spot around the whole year around in the reserve, it is a edangerd specie commoly spotted duerig dry season in the oxbox lakes, creeks and main small tributaries rivers.