“Sharks look smooth, but actually, they’re covered with tiny curving spikes called dermal denticles.
Denticles resemble small, flattened coat hooks, all on top of each other and all curving towards the back of the shark. It’s recently been found that they do the same things that golf ball dimples do – break up the wake and let the shark move through the water faster and with less energy. They are masters of fluid dynamics.”
[Excerpted from io9]