The Game Wardens are two anthropomorphic dogs.
Those two individuals were part of the corps of Duckburg's Game Wardens in 1960, and seemingly high-ranking at that. Puzzled by the Salmon Crooks gang, they hired Gyro Gearloose's help in 1960 to stop them.
Behind the scenes
Those two characters only ever appeared in the 1960 story Fishy Warden.