A large school of Galapagos whaler sharks in deep blue offshore waters. Notice how all but 1 of these sharks are facing a certain direction. They are all facing into the current. Most species of shark must constantly swim to breathe and hence survive. By facing headfirst into the current, more water passes over their gills simulating swiming. This allows them to move slower and conserve energy, an essential adaption out in the blue where food is scarce.