Nature and man combined to obliterate some species in Diawling. Some of the larger mammals perished due to prolonged drought and excessive hunting. The last remaining West African lion (Panthera leo leo) in Diawling was shot in 1970, and the last sighting of the red-fronted gazelle was in 1991. Today, the only mammals in the park are Spotted hyenas, African golden wolves, warthogs, African wildcats, Cape hares and patas monkeys. Other species like the manatee, crocodile, and hippopotamus disappeared with the construction of the dam.
