3D printer makes artificial shark skin
14 May 2014 Last updated at 22:15 BST
Scientists have used a 3D-printed model of shark skin to show how tooth-like scales help the predators to cruise efficiently.
Although engineers have tried to mimic the roughness of shark skin when designing swim suits and even racing cars, the bony denticles themselves have never been so accurately replicated.
The team stuck the new artificial skin onto a small, flexible paddle and studied it in a water tank. Using reflective beads, lasers and a high-speed camera, they were able to see the benefit sharks derive from their unusual scales.
The whirling vortex that can be seen when the paddle moves may help to "suck" the shark forward. It is faster when the paddle is coated with the sharp scales, called denticles.
Video courtesy of L. Wen, J. Weaver, G. Lauder