Sea water is salty and a river is fresh. A bull shark can adjust the salt and water balance in its body, which lets it handle sea water, fresh water and water in between. So it can swim up a river from the sea. Bull sharks have been found hundreds of kilometres from the sea. They have been reported more than 2,000 miles up the Amazon River, in Peru, and as far up the Mississippi River as Illinois. Bull sharks, especially young ones, can travel far up rivers.

A bull shark pup grows inside its mother, fed through a yolk-sac placenta. The mother carries her pups for 10 to 11 months before they are born. She has between 1 and 13 pups at a time, and each pup is born able to swim on its own. A newborn pup is about 55 to 80 centimetres long. In the Gulf of Mexico, bull shark pups are born from April to June.

Female bull sharks are bigger than male bull sharks. As of November 2026, the most a bull shark is reported to weigh is 316.5 kilograms, while the longest one reported was 400 centimetres long.

As of November 2026, the oldest age reported for a bull shark is 32 years. In aquariums, bull sharks have lived 25 years or more.

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.

Bull sharks live in warm coastal water around the world. They live in shallow water near the coast, in bays, estuaries, rivers and lakes, and they are usually found in water less than 30 metres deep. Young bull sharks often grow up in river mouths and bays, where the water is not very salty.

Words to know

• placenta: pup-feeding organ
• opportunistic: eats what's there
• estuaries: river mouths