Peaceful coexistence

To really get an idea of what this picture is about, blow it up. Notice how close the great blue heron and the alligator are to each other. The gator is basking, studiously ignoring the heron, turning its back to the bird. Actually the heron has its back to the gator, too. Do you suppose the critters are communicating with each other?
Perhaps the gator has let the heron know he's full, he really prefers fish to herons, and if the bird don't aggravate him, he'll leave it alone. Or maybe they're identifying with each other as fellow predators...after all, they both eat fish. In that case, who gets first dibs on the first fish to come along? Actually, I have noticed this kind of juxtaposition several times in the Everglades. Quite interesting.