Worldwide in tropical to warm temperate latitudes
Coastal seas and slow moving, coastal rivers (freshwater)
Order Carcharhiniformes (groundsharks), Family Carcharhinidae (requiem sharks)
The bull shark is a predatory species that lives in coastal seas and is the shark with the best ability to move into freshwaters – particularly large, coastal rivers and lakes. They are able to move back and forth between saltwater and freshwater with ease. This behavior brings them into more contact with humans than most species of sharks, and they are therefore responsible for fatally biting more people than any other species.
Reaching lengths of 11 feet (3.5 m) and weights up to nearly 700 pounds (315 kg), the bull shark is one of the largest requiem sharks (Family Carcharhinide). They are aggressive predators and eat a variety of prey. They are known to eat several species of bony fishes and also small sharks, some mammals (both terrestrial and marine), seabirds, and occasionally sea turtles. Large, adult bull sharks do not have any natural predators. Bull sharks do not mature until they are 15 or 20 years old. They mate via internal fertilization and give birth to well-developed, live young. Though they give live birth, bull sharks do not connect to their young through a placenta. Instead, during the gestation period, the embryos survive off of yolk sacs attached to each individual.
Bull sharks do not just venture into freshwater for short periods. They travel far upriver in some places (including the Nicaragua River, the Zambezi River, and the Mississippi River) and there is a semi-permanent population in Lake Nicaragua that was thought until recently to be a separate species. They also apparently give birth in freshwater. During these long periods inland, bull sharks come into close contact with people, and most of the incidents when they have bitten people have been in rivers rather than in the ocean. Even so, these events are extremely rare. Typically, when a bull shark does bite a person, it only takes one exploratory bite and quickly realizes that the person is not its preferred prey. Unfortunately due to their size, even an exploratory bite can be fatal or extremely traumatic.
Bull sharks have been fished, commercially, in the past, but currently the biggest threat that they face is accidental capture in fisheries targeting other species. Most of these accidental captures take place when these sharks are upriver. They are also occasionally targeted in shark culling operations meant to promote the safety of beachgoers and other tourists. This activity has not been proven to be effective in protecting swimmers and is generally frowned upon by conservationists and scientists. As a result of the risks that bull sharks face throughout their range, the species is considered near threatened with extinction. If population trends are not reversed, this species may be at greater risk.
Oceana joined forces with Sailors for the Sea, an ocean conservation organization dedicated to educating and engaging the world’s boating community. Sailors for the Sea developed the KELP (Kids Environmental Lesson Plans) program to create the next generation of ocean stewards. Click here or below to download hands-on marine science activities for kids.