They're basically the puppies of the ocean.
The photographer behind Underwater Dogs runs Second Chance Photos, a service that makes adoptable animals more appealing in their photos.
They're just playing, but they look so intense. More beautiful underwater dog photography by Seth Casteel here.
BALLBALLBALLBALLBALLBALLBALL! That's basically all I've got to say about this awesome photo, other than to note that the photographer, Seth Casteel, has an entire "underwater dogs" gallery on his website. You're welcome. (via Reddit)