This group dominates the tropical shark fauna in the diversity of species and often in numbers of individuals. They have circular, widely spaced eyes. Five of the species are small and do not exceed five ft in length. The other four reach lengths of between 10 and 17 ft. Confined to coastal and offshore continental and insular waters, from the intertidal and surface down to at least 900 ft.
None is benthic, deepwater, or oceanic.
All warm temperate and tropical seas. Bony fishes, other sharks, batoids, squid, octopuses, and cuttlefish, crabs, shrimps and other crustaceans and sea-snails. Hammerheads swing their heads back and forth while they swim. This may be a way of increasing their chances of detecting food.