Underwater blue whale photo, Balaenoptera musculus, #01902
Note the hydronamic shape of a blue whale's rostrum (head). This, along with its broad, flat fluke and relatively long, narrow body, is an adaptation to the considerable travel blue whales undergo transitting from warm calving waters to cool food-rich waters. In this photo, the outline of this blue whale's U-shaped upper lip bone is easily discerned. This bone is more massive than any other in the animal kingdom.
Blue whale, the largest animal ever to inhabit earth, swims through the open ocean, underwater view.