Shark skin has long fascinated humans from fishers to physicists. That’s because shark scales have evolved into tiny three-dimensional, anvil-shaped structures called denticles that help these animals swim at furious speeds. Attacking Mako sharks, for example, have been clocked at over 70 km/h. By comparison, an Olympic sprint swimmer might reach just 5 km/h.
The thinking among hydrodynamicists is that the strange shape of shark denticles must play a crucial role in shark locomotion. And if they can somehow copy this process, it ought to be possible to make artificial shark skin that could help humans or submarines swim faster.
But nobody is quite sure how denticles work. The problem is that most experiments have been done with simplified structures or with shark skin itself, which loses its special properties when removed from the fish. So, while hydrodynamicists have made progress with certain simple skin structures, the way denticles reduce drag is largely unknown.
