Highly magnified hand-colored scanning-electron-micrograph of Mako (Isurus oxyrinchus) shark skin.
Sharks have a covering of dermal denticles that protects their skin from damage and parasites, in addition to improving their fluid dynamics. Single striatet scales (i.e. ‘riblets’) are overlapping like roof tiles.
Each riblet produces microscopically small turbulences, creating a very thin film of water turbulences around the sharks body to reduce lateral drag. This enables Mako sharks to swim as fast as 70 kilometres/h. This effect is only efficient for fast swimming and similar structures are used for submarines, boats and airplanes.