The management of drag acting on solid surfaces by water flow is important for saving energy of ship and pipelines. The present author has investigated the drag on algal blades and dolphin skins as examples of the bio-inspired management of drag. This report demonstrates our recent numerical and experimental results, such as a decrease in the wall-shear stress by the polysaccharide models on the deforming film and the low values of drag coefficients of the small wavy plate. These changes in drag are caused by the modification of coherent structure near the functional, deformable surfaces of sea life.