Three flying reptiles from Earth's distant past glide above the gray Pacific, far beyond the rollers breaking on the shore of Point Reyes, California. They flap their wings slowly for a few beats, gain some altitude, then turn toward the beach. One peels out of formation and dives into the water with a splash, sinking just as far as its shoulders to snatch a fish with its long snout. Then, with a few powerful wing strokes, the beast takes off, using its webbed feet to hop off the waves until it clears the water. As it draws near, the primeval pterosaur transforms into an ordinary brown pelican.

Keven Padian, a paleontologist at the University of California, Berkeley, stands on the beach