However, it turns out that a unique shark species, the bull shark, tends to swim outside the box—and right into the freshwater of the Mississippi River. Could bull sharks really swim that far ...

Freshwater shark: Alone among the sharks ... These are the only two specimens ever found of this new species, whose gaping mouth inspired the name "megamouth." Lowest note a shark can hear ...

While the size and scale of the lakes may resemble oceans, the Great Lakes are freshwater systems. Most shark species require saltwater to maintain the internal salt balance they need to survive.