By Boris Nagoda
Three shark species are responsible for the majority of attacks on humans: white sharks, tiger sharks, and bull sharks. White and tiger sharks are well known as some of the largest and most aggressive shark species. Bull sharks are smaller, relatively speaking, but are thought to have attacked more people than any other species. What makes bull sharks so dangerous?
Bull sharks (Carcharhinus leucas) are medium-sized sharks. Females reach about 12 feet and 500 pounds, although the average length is about 8 feet. Bull sharks are named for their very short, blunt snout. Like many sharks, they are pale to dark gray with a white underside.
Bull sharks are found along warm coasts worldwide, areas where many swimmers are present. Their wide range and preference for near-shore environments like estuaries, harbors, beaches, and creeks increases the likelihood of encounters with humans. In the United States, they are found off southern California and from New York to south Florida. They are very common off southeastern Florida and throughout the Gulf of Mexico.
Bull sharks are noted for their ability to tolerate freshwater, unlike most sharks. Bull sharks have been found 2,500 miles up the Amazon River, and have been caught in the Mississippi River as far north as Illinois. Not surprisingly, most shark attacks in freshwater are attributed to bull sharks.
Like all sharks, bull sharks did not evolve to eat humans. Bull sharks prey on dolphins, sea turtles, shellfish, and finfish, including smaller sharks. However, they are aggressive predators. Often hunting in murky water, they may mistake swimmers for prey and bite once before realizing their mistake. These “hit and run” attacks often occur in the surf zone and don’t usually result in life-threatening injuries. However, bull sharks might also try to see if swimmers are potential prey. In “bump and bite” attacks, bull sharks circle swimmers and bump them with their snouts prior to attacking. In this type of attack, the shark intends to feed and usually bites repeatedly, often resulting in severe injury or death. Researchers have raised the possibility that some bull shark attacks may be territorial in nature.
Because they are common and aggressive sharks in warm, near-shore waters where swimmers are present, bull sharks have been implicated in more attacks than any other species. However, it’s important to note that the odds of being attacked by any shark species are small – only about 70 shark attacks are reported per year, worldwide. Although bull sharks are dangerous, they have more to fear from humans than vice versa.
Bull sharks are fished for meat and skins; they are currently common, but shark numbers are decreasing worldwide due to overfishing, and many species are endangered. Bull sharks may sometimes prey on people, but people frequently prey on them.
Image: “Bullshark”. Licensed under Public Domain via Commons – https://commons.wikimedia.org/wiki/File:Bullshark.JPG#/media/File:Bullshark.JPG