The bull shark, Carcharhinus leucas, also known as the Zambezi shark or unofficially Zambi in Africa and Nicaragua shark in Nicaragua, is a shark commonly found worldwide in warm, shallow waters along coasts and in rivers. The bull shark is known for its aggressive nature, predilection for warm shallow water, and presence in brackish and freshwater systems including estuaries and rivers. The bull shark can thrive in both saltwater and freshwater and can travel far up rivers.