Aerial view of a fin whale performing a ~90° surface roll while lunge feeding. As the roll is initiated the flippers are adducted and thus obscured by the body. In this position one or both flippers may be used to generate asymmetric lift but their orientation would not be visible by the camera. Video courtesy of Wes Arnold, CineAire Aerial Videography.
Paolo S. Segre, David E. Cade, Frank E. Fish, Jean Potvin, Ann N. Allen, John Calambokidis, Ari S. Friedlaender, and Jeremy A. Goldbogen
Journal of Experimental Biology
2016. 219:3315-3320; doi: 10.1242/jeb.137091