Scientists who want to learn where a bull shark goes can attach a satellite tag to it. One study of this kind, run from 2005 to 2007, tagged 18 bull sharks with a mean size of 164 centimetres, measured as fork length. The sharks kept their tags for up to 85 days, with a median of 30 days, and during that time they generally travelled 5 to 6 kilometres a day, covering an average of 143.6 kilometres in all. The tagged bull sharks stayed mostly between 26 and 33 degrees Celsius. In a satellite-tag study, bull sharks spent most of their time in water shallower than 20 metres. A fish database gives the depth range of the bull shark as 1 to 164 metres, and it says bull sharks are usually found at depths of 1 to 30 metres.

A different kind of tracking followed young bull sharks in an estuarine river system, and it found that the sharks moved upstream during the day and downstream at night. Bull sharks, especially young ones, can travel far up rivers, and they have been found hundreds of kilometres from the sea. Some have been reported more than 2,000 miles up the Amazon River, in Peru, or as far up the Mississippi River as Illinois. Bull sharks have also been recorded repeatedly in the Potomac River, and they have a semi-permanent population in Lake Nicaragua. In the western Atlantic, bull sharks travel north along the coast of the United States in summer.

Several different numbers describe how big a bull shark can be. Bull sharks can grow to a total length of about 340 centimetres, and the longest bull shark reported was 400 centimetres long. One aquarium page gives the maximum length as about 3.5 metres and the maximum weight as 230 kilograms. As of November 2026 the most a bull shark is reported to weigh is 316.5 kilograms. A newborn bull shark weighs 1.5 to 3.0 kilograms and is about 60 to 71 centimetres long. According to one aquarium, an average female is about 2.4 metres long and weighs 130 kilograms, and an average male is about 2.3 metres long and weighs 95 kilograms. Female bull sharks can reach about 4 metres long, while male bull sharks usually grow to about 3.6 metres.

In a 2024 study, bull sharks were described as dietary generalists that feed on a wide range of prey. Bony fishes and small sharks make up the vast majority of a bull shark's diet, and one study found that they commonly eat catfish of the family Ariidae. Bull sharks are opportunistic hunters that eat many different kinds of prey, such as fish, rays, crabs and squid. A bull shark usually hunts alone, and it often swims slowly near the bottom until prey appears. Over short distances, bull sharks have been recorded swimming at about 19 kilometres an hour. A bull shark's upper teeth are triangles with jagged edges, and bull sharks have small eyes compared with most other sharks in their family.

A bull shark can adjust the salt and water balance in its body, and its gills, rectal gland, blood, hormones and kidneys all play a part as it moves between salt and fresh water. Bull sharks caught in fresh water had lower salt levels in their blood than bull sharks caught in salt water. In fresh water, the kidneys work hard to keep salt in the body. Young bull sharks enter estuaries and lagoons with low salt as easily as adults do, and they often grow up in river mouths and bays. Bull sharks can live in water as salty as 53 parts per thousand, which is saltier than ordinary sea water.

Words to know

• satellite: space-linked
• median: the middle number
• dietary: about food