Bull shark

The **bull shark** (*Carcharhinus leucas*), or **Zambezi shark**, is a species of shark of the genus *Carcharhinus*.

The shark grows to a maximum length of 11.5 feet (3.5 metres), but is usually 7.3-7.8 feet (2.2-2.3 metres) long. It is found in tropical and subtropical coastal waters worldwide, as well as river systems and freshwater lakes.

This species is listed as Near Threatened by the IUCN and is considered to be the third most dangerous shark in the world.

## Description
Bull sharks have a very sturdy body, and have a blunt, rounded snout, giving the bull shark its name. 

The first dorsal fin is large and widely triangular with a pointed tip. The second dorsal fin is noticeably smaller. The pectoral fins are also large, and have sharp tips. 

Bull sharks have quite small eyes as compared to other carcharhinid sharks, which might mean that vision is not a very important hunting tool for this species (which is usually found in muddy waters). 

Bull sharks are usually pale to dark grey above, and their undersides are white. In young bull sharks, the fins have black tips which turn to a dusky colour as they grow.

### Teeth 
The teeth of the upper jaw are wide, triangular, and heavily jagged. The teeth of the lower jaw have a wide base, and are narrow, triangular, and are finely jagged. The front teeth are raised and are nearly symmetrical, while the back teeth are more slanted in shape.

### Size 
The size at birth is around 29 inches (75&nbsp;cm). 

Females are larger than males, reaching a length of around 7.8 feet (2.4 metres) as adults, and weighing around 285 pounds (130&nbsp;kg). This is the result of a longer lifespan of about 16 years, compared to 12 years for males. Males reach a length of around 7.3 feet (2.2 metres), and weigh 209 pounds (95&nbsp;kg). The maximum weight is over 500 pounds (230&nbsp;kg). 

The growth rates calculated from captive bull sharks were estimated to be about 11 inches (28&nbsp;cm) per year in the first years of life, slowing to half that rate after about 4 years of age.

## Habitat
The bull shark is found in tropical and subtropical coastal waters worldwide as well as in many river systems and some freshwater lakes. It likes to live in shallow coastal waters less than 100 feet deep (30 metres), but ranges from 3–450 feet deep (1–135 metres). 

It commonly enters estuaries, bays, harbours, lagoons, and river mouths. It is the only known shark species which is found in freshwater, and can spend long periods of time in such environments. It is not likely that the Bull shark's entire life cycle is within a freshwater system, however. There is evidence that they can breed in freshwater, but not as regularly as they do in estuarine and marine habitats. 

Young bull sharks enter estuaries with low salt contents and lagoons as readily as adults do, and use these shallow areas as nursery grounds. They can also live in waters with high salt contents; as high as 53 parts per thousand.

Even though humans are not in their diet, bull sharks have been known to be very aggressive towards humans. This shark can be a danger to humans since many people don't realize it lives in rivers and freshwater. 

Almost all of the close-to-shore shark attacks on humans have been caused by this species.They are listed as the 3rd largest risk to humans when it comes to sharks. They are only behind the Great White shark and the tiger shark.

Although the bull shark has no real predators, young bull sharks have been known to fall prey to tiger sharks, sandbar sharks, and even adult bull sharks. 

Parasites, like *Pandarus sinuatus* and *Perissopus dentatus*, have been found in bull sharks. They parasitize the body surface of this shark. Bull sharks usually migrate to river mouths to mate and have their young.

## Danger to humans
According to the International Shark Attack File (ISAF), bull sharks have been responsible for at least 69 unprovoked attacks on humans around the world, 17 of which have resulted in deaths. However, this species is likely to be responsible for many more attacks, and has been considered by many experts to be the most dangerous shark in the world. 

Because of its large size, its ability to enter freshwater, and the fact that it is found inshore, it might be more of a threat to humans than either the Great White shark or the tiger shark. Since the Bull shark is found in many Third World regions (including Central America, Mexico, India, east and west Africa, the Middle East, southeast Asia, and south Pacific islands), attacks are often not reported. The Bull shark is also not as easily identifiable as the Great White or the tiger shark, so it is likely to be responsible for a large percentage of attacks with unidentified culprits.

### 1916 New Jersey attacks 
The bull shark has been considered to be the culprit in the infamous series of five shark attacks in New Jersey in 1916, which resulted in four deaths over a 12-day period. Three of these attacks happened in Matawan Creek, a shallow tidal river, only 40 feet (12 metres) across, 1.5 miles (2.4&nbsp;km) from bay waters, and over 15 miles (24&nbsp;km) from the open ocean; not a location where any other large shark species would likely be found. A 7.5 foot (2.25 metres) Great White was captured two days after the last attack, however, just 4 miles (6.4&nbsp;km) from the mouth of Matawan Creek, and contained human remains in its stomach. A 9-foot (2.7 m) bull shark was also captured a day later only 10 miles (16&nbsp;km) from Matawan. This has been a topic of debate for many years, and there is evidence that points at both the bull shark and the Great White as the culprits.

## Related pages 
* Shark
* Cartilagenous fish
* Near-threatened species

## References