Gabriel Rojo / Marsh deer (Blastocerus dichotomus) male with Cattle tyrant (Machetornis rixosus) on back, Ibera Marshes, Corrientes Province, Argentina.

Luiz Claudio Marigo / Young female Marsh Deer (Blastocerus dichotomus) in profile. Endangered species. The Pantanal wetlands of Mato Grosso State, Brazil, October.

Gabriel Rojo / Marsh deer (Blastocerus dichotomus) feeding in wetland. Pantanal, Mato Grosso, Brazil.

Gabriel Rojo / Marsh deer (Blastocerus dichotomus) walking across track in forest. Pantanal, Mato Grosso, Brazil.

Nick Garbutt / Marsh deer (Blastocerus dichotomus), stag. Pousada Araras, northern Pantanal, Mato Grosso, Brazil.

Franco Banfi / Marsh deer (Blastocerus dichotomus) and Capybara (Hydrochaeris hydrochaeris) resting in stream, Pantanal, Mato Grosso, Brazil

Luke Massey / Marsh deer (Blastocerus dichotomus) in water Pantanal, Brazil.

Luke Massey / Marsh deer (Blastocerus dichotomus) drinking water Pantanal, Brazil.

Gabriel Rojo / Tourists on boat, watching Marsh deer (Blastocerus dichotomus) Ibera Marshes, Corrientes Province, Argentina. August 2009.

Gabriel Rojo / Marsh deer (Blastocerus dichotomus) male, Ibera Marshes, Corrientes Province, Argentina

Gabriel Rojo / Jabiru (Jabiru mycteria) wading with Marsh deer (Blastocerus dichotomus) behind, Ibera Marshes, Corrientes Province, Argentina

Gabriel Rojo / Marsh deer (Blastocerus dichotomus) male with Cattle tyrant (Machetornis rixosus) Ibera Marshes, Corrientes Province, Argentina