River sharks (genus Glyphis)
River sharks are true freshwater sharks, unlike bull sharks which are euryhaline; the two may be confused in freshwater settings.
Photo byGerald Schömbs
Species Guide
What to know about bull sharks
A clean field guide focused on habitat, identification, behavior, and conservation context without burying the useful parts.
The bull shark (Carcharhinus leucas) is a requiem shark commonly found worldwide in warm, shallow waters along coasts, in estuaries and in rivers. It is euryhaline and can thrive in both salt and fresh water, and individuals have been recorded traveling far upriver — for example, up the Mississippi River as far as Alton, Illinois, about 1,100 kilometres from the ocean. Bull sharks are known for their aggressive nature; larger individuals are responsible for a large part of nearshore shark attacks and may account for many attacks involving unidentified species. Unlike river sharks of the genus Glyphis, bull sharks are not true freshwater sharks despite their ability to survive in freshwater habitats. Bull sharks are listed as vulnerable on the IUCN Red List. Ongoing shark-culling efforts near beaches to protect beachgoers are among the causes contributing to continuing population declines. The species also appears on the 2000 colones banknote from Costa Rica.
Bull shark populations are continuing to decrease; ongoing shark-culling efforts near beaches to protect beachgoers are cited as one cause.
Euryhaline species that commonly occurs in warm, shallow coastal, estuarine and lower river reaches and can travel far upriver from the ocean.
Identification
How to identify bull sharks
The visual markers divers can use underwater, plus the species most likely to cause confusion.
Common lookalikes
Range and Movement
How bull sharks move through the world
The broad range, seasonal movement, or migratory behavior that shapes where divers encounter this species.
Euryhaline species that commonly occurs in warm, shallow coastal, estuarine and lower river reaches and can travel far upriver from the ocean.
Conservation
What is happening with Bull Sharks
Status, pressure, and protection context grounded in cited sources rather than filler.
Bull shark populations are continuing to decrease; ongoing shark-culling efforts near beaches to protect beachgoers are cited as one cause.
Main threats
Shark culling near beaches
Ongoing shark-culling efforts intended to protect beachgoers have contributed to population decreases.
Responsible Encounters
How to dive with bull sharks
Conservation-minded guidance for divers who want the encounter without adding pressure.
Give bull shark space, avoid blocking the animal's path, and follow local site and operator rules for wildlife interactions with sharks.
Field Notes
Interesting things worth knowing
Useful species context that makes the encounter more meaningful once you are underwater.
Field notes
Euryhaline
Bull sharks can thrive in both salt and fresh water.
Long river movements
They have been recorded traveling up the Mississippi River to Alton, Illinois, about 1,100 kilometres from the ocean.
Cultural appearance
The bull shark appears on the 2000 colones banknote from Costa Rica.
Common names
Also known as the Zambezi shark (informally 'zambi') in Africa and the Lake Nicaragua shark in Nicaragua.
FAQ
Frequently asked questions
Clear planning and conservation answers written for search visibility and AI retrieval.
Research Sources
Bull Shark information sources
Primary and credible references behind the field-guide and conservation claims on this page.
Sources 4Last Updated
Bull Shark (Carcharhinus leucas) | U.S. Fish & Wildlife Service · Reference · U.S. Fish & Wildlife Service
Primary wildlife guide source.
Florida Museum · Reference · Florida Museum
Supporting wildlife source.
NOAA Fisheries · Reference · NOAA Fisheries
Supporting wildlife source.
Bull shark · Encyclopedia · Wikipedia
Supporting wildlife source.
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