The notorious white shark is credited with more fatal attacks on humans than any other shark species. Some think its aggression is a case of mistaken identity, since from below swimmers and surfers can resemble the shark's common meal of seal or sea lion, but others believe a great white will mouth any large unknown object to test its edibility.

The tiger shark is second only to the white shark in its number of unprovoked attacks on humans. What makes these sharks particularly threatening to swimmers and divers is a combination of their large size, hunting style (close to shore and the ocean's surface), natural curiosity and indiscriminate appetite; tiger sharks will eat just about anything that floats.

The bull shark ranks third in its number of unprovoked attacks on humans; however, it is less physically distinguishable than other sharks, and is likely responsible for many of the attacks by unidentified species. The combination of its big size and its habitat — which includes populous tropical areas as well as freshwater bodies — makes it more of a potential threat than either white or tiger sharks.

The International Shark Attack File ranks hammerhead sharks seventh among the sharks most dangerous to humans (after white, tiger, bull, sand tiger, blacktip and requiem sharks). Because hammerhead species are difficult to distinguish from each other, few of their reported attacks can be attributed to the great hammerhead in particular. However, it is supposed that because of its large size and varied diet the species poses a potential threat to humans.