These are mammals in the video.  They are warm blooded and breathe air. Because they must breathe they are required to return to the surface.  But in the video they seem to be playing, jumping, enjoying the jump into the heavens and out of the waters where they live.  One of the dolphins leaps and twists like one of the Olympic events we just finished watching.

The upward leap seemed a symbol to me of what all life here was intended to do: reach up joyfully to that God who gave us life.  Hope you enjoy the video and song as much as I did as I watched it with a daughter last night.