Pulsing motion sucks water toward jellyfish and pushes it forward

Video of a swimming moon jellyfish (Aurelia aurita) showing the visualized fluid vectors (colored arrows) and vorticity (spin) associated with the fluid as result of the swimming motion. Colors indicate direction of spin with blue being clockwise and red representing counterclockwise fluid rotation generated by the animal as it swims. Playback is approximately 1/5 of real time. Brad Gemmell, University of Southern Florida.