What’s the furthest from the ocean a shark has ever been spotted?
Currently, the bull shark that was sighted in Iquitos, Peru, is the furthest inland a bull shark has even been recorded. Still, there are plenty of other examples of just how far they can travel through freshwater systems. In the United States, bull sharks often travel up the Mississippi River and head north. The furthest north that a bull shark has been recorded in the Mississippi is in Alton, Illinois. Alton is 15 miles north of St. Louis and 1,750 miles north of the Gulf of Mexico, where the sharks usually live. Additionally, bull sharks have been seen in the Ohio River as far north as Manchester, Ohio, and in the Potomac River in Maryland. Australia is also home to bull sharks. After the flooding of the Logan and Albert Rivers in 1996, a group of sharks was trapped in golf course lakes at the Carbrook Golf Club in Queensland, Australia. Now, they are permanently living in the lakes, with the Shark Lake Challenge tournament being named after the population.
How do bull sharks live in freshwater?
Part of what makes bull sharks so adaptable is their evolutionary adaptations and freshwater tolerance. Only a few species of fish are able to switch between fresh and salt water, with the bull shark being among them. This advantage likely occurred during the last ice age when there was a population bottleneck. Bull sharks can live in freshwater through specialized organs like the rectal gland and an adapted kidney, liver, and gills. In saltwater, bull sharks excrete excess salt through their rectal glands but reduce this action while in freshwater. If needed, a bull shark can live its entire life in freshwater, even so far as to reproduce in it!
Are bull sharks dangerous to humans?
Bull sharks are incredibly dangerous to humans if they are in the same area. They are among the most dangerous sharks in the world by number and are known for their aggressive nature. In fact, part of what gives bull sharks their name is their tendency to ram a target before biting it. They generally prefer dark, murky waters to hunt and will eat almost anything they can find.
