The three most interesting behavioral characteristics of bull sharks are primary reasons that they are considered among the most dangerous sharks in the world. These fish are much more aggressiveness than most sharks, prefer shallow waters and tend to travel great lengths, showing up in some unexpected locations. Their unpleasant temperament and tendency to be where humans are has become legendary among us Florida natives; a legend that, as more and more people flock towards warm coastal areas, has unfortunately become true.
Bull sharks are notoriously aggressive and territorial, feeding on a wide array of sea life, including fish, other sharks, rays, dolphins, and turtles. They have also been linked to at least 77 unprovoked attacks on humans, though many experts believe that bull sharks are responsible for many attacks from unknown culprits or that were attributed to other types of shark. Although it is believed that many shark attacks are typically cases of mistaken identity, some bull sharks may attack out of curiosity or territoriality. It is also interesting to note that even though land-dwelling mammals aren't typically on the menu for bull sharks, some specimens have been found to have dogs, humans and even hippopotamuses in their stomachs.
Bull sharks prefer water that is no deeper than 100 feet, but are often found in much shallower waters than that. Despite growing to an average length in excess of 7 feet, these creatures often hunt in shallow bays, estuaries, and in the surf, sometimes in water only 3 feet deep. A lifeguard once told me that bull sharks can be encountered anywhere past the breakers, not a comforting thought for a 10-year old boy who couldn't stay away from the ocean.
Bull sharks are notorious for showing up in some unexpected locations, showing a great willingness to travel for food. For starters, they are one of only two species of shark that are known to tolerate both fresh and salt water for extended periods of time. I've heard of fisherman encountering these beasts 100 miles up the St. Johns River. More impressive are the documented cases of bull sharks being found 2,200 miles up the Amazon River and 1,800 miles up the Mississippi River. Bull sharks may be found as far north as Massachusetts in the summer, and can be encountered on both the Atlantic and Pacific coasts of North and South America, on both coasts of Africa, off of India, and in Australia.
The bull shark's wide range and tolerance of both coasts and shallow freshwater rivers put them in contact with humans at a greater frequency than other "man-eaters"; combined with their nasty dispositions, this makes the bull shark perhaps the most dangerous shark in the world.