Bull shark
A stout requiem shark that thrives in fresh and salt water.
The bull shark is a large, aggressive requiem shark found in warm coastal waters and rivers worldwide. It is one of the few sharks capable of living in freshwater for extended periods, leading to frequent human encounters.
- Can travel far up rivers like the Amazon and Mississippi.
- One of the few sharks that thrive in fresh water.
- Listed as Vulnerable on the IUCN Red List.
- Females can reach lengths of up to 4 metres.
- Known for aggressive behaviour and nearshore attacks.
What it is
The bull shark is a stocky, powerful requiem shark with a broad, flat snout and grey upper body. Females grow larger than males, reaching up to four metres in length. It lacks an interdorsal ridge and has a second dorsal fin smaller than the first. This species is renowned for its ability to survive in both salt and fresh water, a trait known as euryhalinity. Its robust build and unpredictable behaviour contribute to its common name.
Where it lives
This shark inhabits warm coastal waters globally, from Massachusetts to Brazil and Morocco to Angola. It frequently enters rivers and lakes, travelling far inland. Records show presence in the Mississippi, Amazon, Ganges, and Zambezi rivers. It has been spotted in Lake Nicaragua and even trapped in a golf course lake in Australia for over a decade. It prefers shallow waters but can dive to depths of 150 metres.
How it lives
An apex predator, the bull shark hunts bony fish, other sharks, stingrays, and occasionally terrestrial mammals. It uses a bump-and-bite technique in murky waters where visibility is low. While usually solitary, it may pair briefly to hunt. If threatened, it can regurgitate stomach contents to distract predators and escape. Its diet varies with availability, reflecting its opportunistic feeding habits.
Breeding and life cycle
Mating occurs in late summer and early autumn within bays and estuaries. After a twelve-month gestation, females give birth to one to thirteen live young. These pups are born free-swimming in protected nursery areas like coastal lagoons and river mouths. Young sharks remain in low-salinity zones until they develop greater tolerance for salt water, which aids their survival.
Fish and people
Due to its presence in shallow waters and rivers, the bull shark is involved in many nearshore attacks. This aggression has led to culling programmes in some beach areas. It appears on Costa Rican currency. Local names vary widely, including Zambezi shark and river shark. Its ability to enter freshwater systems makes it a unique subject of scientific study regarding osmoregulation.
Status and threats
The International Union for Conservation of Nature lists the bull shark as Vulnerable. Populations are declining due to fishing pressure and habitat loss. Shark-culling efforts near beaches also contribute to reduced numbers. Despite its wide range, these threats pose significant risks to long-term stability. Conservation measures are needed to protect this ecologically important predator.
Questions people ask about Bull shark
Can bull sharks live in fresh water?
Yes, they are euryhaline and can adapt to fresh water. They use special organs to regulate salt balance. Young sharks often stay in rivers for safety before moving to the sea.
How big do bull sharks get?
Adult females average 2.4 metres, while males are slightly smaller. The largest recorded specimen was a female measuring exactly 4.0 metres and weighing over 600 kg.
Why are they called bull sharks?
The name comes from their stocky shape, broad snout, and aggressive, unpredictable behaviour. They are wider and heavier than other requiem sharks of similar length.
Where do bull sharks give birth?
They give birth in protected nursery areas such as coastal lagoons, river mouths, and estuaries. These low-salinity environments help protect the young from predators.
Good reading and sources
- Shark attacks bring panic to SydneyThe Guardian, Article
- Australia flooding: Brisbane resident's experienceBBC, Article
- Sharks on a Golf Course Made a Watery Grave Unlike Any Other (Published 2023)The New York Times, Article
The facts on this page come from the Wikipedia article "Bull shark", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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