Animal · United States, Mexico, Nicaragua
Bull shark
Carcharhinus leucas — the name this animal has in the language scientists everywhere share.
The bull shark is a heavy, blunt-nosed shark that can live in salty sea water and in fresh river water, which almost no other shark manages. It has turned up thousands of kilometres up the Amazon and the Mississippi, far from any coast.
Picture credit: Jerome Paillet (IFREMER, Laboratoire d'Océanographie Physique et Spatiale, Centr (CC BY 4.0) · Albert kok (Public domain) · Wikimedia Commons
Where does the bull shark live?
Home: Warm coasts, river mouths and even rivers inland.
In the wild it lives in these countries: the United States, Mexico, Nicaragua, Brazil, Australia, South Africa, India, Mozambique.
Conservation status from the IUCN: vulnerable.
The short profile
Fully grown: 2 to 3.4 m long, rarely up to 4 m. It weighs about 115 kilograms. On the menu: meat.
The story behind it
Most sharks would die in a river, because fresh water pulls the salt out of their bodies. The bull shark solves the problem with unusually good kidneys and a gland near its tail that throw away or keep salt as needed, so it can swim from the sea into a river and back again. Young bull sharks often grow up in warm, muddy river mouths, where bigger predators cannot follow them. An adult is short and thick, with a rounded snout, small eyes and the strongest bite ever measured in a shark. Because it hunts in shallow, cloudy water close to the shore, it meets people more often than most sharks do. Fishing and the loss of its river nurseries have made it rarer, and the species is now listed as vulnerable.
Find it on the globe
Bull shark is there as a tiny animated figure that breathes and looks around. From far away the planet is only a blue ball; detail arrives as you zoom in, and this one appears once you are close enough. Open it on the globe.
It sits at its real coordinates, not near them — the same numbers listed in the facts above. Switch off the layer for this kind of place and it disappears again; the buttons for that are down the right-hand edge.
Questions children ask
Can bull sharks really live in rivers?
Yes. Their kidneys and a special gland let them keep the right amount of salt in fresh water, so they swim far upstream. Bull sharks have been recorded in the Amazon, the Mississippi, the Ganges and Lake Nicaragua.
Are bull sharks dangerous?
They are counted among the three shark species involved in most attacks on people, mainly because they hunt in shallow, murky water where swimmers also go. Attacks are still rare, and a bull shark is not looking for humans.
What do bull sharks eat?
Mainly bony fish and stingrays, plus smaller sharks, including young bull sharks. Turtles, seabirds, crabs and dolphins turn up on the menu too, so the diet changes with whatever the muddy water offers.
Where these numbers come from
Every figure on this page was checked against public reference sources before publication. Where sources genuinely disagree, the text says so.
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