What we found is that as the shark skin membrane moves, there is a separation of flow. The denticles create a low-pressure zone, called a leading-edge vortex, as the water moves over the skin," he said. "You can imagine this low-pressure area as sucking you forward. The denticles enhance this leading-edge vortex. So my hypothesis is that these structures that make up shark skin reduce drag, but I also believe them to be thrust-enhancing