Giles Laurent · CC BY-SA 4.0Marsh deer
Blastocerus dichotomus · guasu puku
South America's largest deer, with branching antlers and black legs: king of the marshes.
What it is
It reaches up to 2 m in length and 1.20 m at the shoulder. It lives in marshes, floodplains and lagoons with tall vegetation, where it feeds on aquatic plants. Its hooves spread wide and are webbed, allowing it to walk through mud. Today it survives in isolated populations in the Paraná and Paraguay basins and is listed in CITES Appendix I.
Did you know…?
Its Guaraní name, guasu puku, means “long deer” or “big deer.”
Where
The Ñeembucú marshes, Lake Ypoá, the wetlands of the Lower Chaco (Tinfunqué) and the Pantanal (Río Negro).
Researched and reviewed in September 2026 with 3 sources. A second reviewer checked dates, coordinates and lodging. Hours and prices may change.