The bull shark, Carcharhinus leucas, also known as Zambezi shark or unofficially known as Zambi in Africa and Nicaragua shark in Nicaragua, is a shark common worldwide in warm, shallow waters along coasts and in rivers. The bull shark is well known for its unpredictable, often aggressive behavior. Since bull sharks often dwell in shallow waters, they may be more dangerous to humans than any other species of shark, and, along with tiger sharks and great white sharks, are among the three shark species most likely to attack humans.
Unlike most sharks, bull sharks tolerate fresh water and can travel far up rivers. They have even been known to travel as far up as Indiana in the Ohio River, although there have been few recorded attacks. As a result, they are probably responsible for the majority of near-shore shark attacks, including many attacks attributed to other species. However, bull sharks are not true freshwater sharks (unlike the river sharks of the genus Glyphis)