The bull shark, Carcharhinus leucas, also known as the bull whaler, Zambezi shark or colloquially Zambi in Africa and Nicaragua shark in Nicaragua, is common worldwide in warm, shallow waters along coasts and in rivers. The bull shark is well-known for its unpredictable, often aggressive behavior.
Unlike other marine sharks, bull sharks tolerate fresh water. They can travel far up rivers. As a result, they are probably responsible for the majority of attacks on humans that take place near the shore, including many attacks attributed to other species. However, bull sharks are not true freshwater sharks (unlike the river sharks of the genus Glyphis).

Taxonomy
The bull shark is found all over the world in many different areas. The bull shark has been known to travel long distances. The bull shark is common in the coastal areas of warm oceans, in rivers and lakes, and in both salt and fresh water. They are found to a depth of 150 m, but does not usually swim deeper than 30 m.
Until very recently, researchers thought the sharks in Lake Nicaragua were a separate species because there was no way for the sharks to move in or out. It was discovered that they were jumping along the rapids just like salmon. Bull sharks tagged inside the lake were later caught in the open ocean.[1]

Distribution and habitat
Bull sharks are large and stout. Males can reach 2.1 metres (6.9 ft) and weigh 90 kilograms (198.4 lb). Females can be much larger: 3.3 metres (10.8 ft) and 318 kg (700 lb). Bull sharks are wider than other sharks of comparable length, and are grey on top and white below. The second dorsal fin is smaller than the first.

Diet
Bull sharks are solitary hunters..
Many experts think the bull shark is responsible for most of the deaths around the Sydney Harbour inlets in the past. Most of these attacks were previously thought to be great whites. In India the bull shark cruises up the Ganges River where it has killed and attacked a large number of people. It also eats the corpses that the Indians float on the river. Many of these attacks have been wrongly blamed on the Ganges Shark Glyphis gangeticus, a fairly rare species that is probably the only other shark that can live comfortably in both saltwater and freshwater. The grey nurse shark was also blamed in the sixties and seventies.

Reproduction

List of sharks
List of fatal, unprovoked shark attacks in the United States by decade.