Seabirds wheel over the green ocean, concentrating their attention on a shoal of fish feeding in the surface waters. One by one the birds dive, splashing into the depths and surfacing again with their catches. Suddenly a great turmoil churns up the water, and in a cloud of spray, pointed heads on long thin necks burst from the surface and shoot skywards, snapping and snatching at the wheeling flock. When they subside once more into the sea the flock of birds has scattered in panic, and many of their number have disappeared.
The necks belong to birdsnatchers, the specialized, bird-eating elasmosaurs. In appearance they are very similar to conventional elasmosaurs that have existed for the past 100 million years. The seas have remained relatively unchanged, as has the fish population, and so the elasmosaur shape has proved a successful and long-lasting one. The main adaptation evolved by the birdsnatcher is its ability to catch seabirds and pterosaurs (such as soars). It lives chiefly on fish, but now and again a school of birdsnatchers will work together to seize a flock of birds or pterosaurs from the sky. With necks held back they approach an area where birds and/or pterosaurs are fishing. Then they all break the surface at the same time and thrust their necks quickly upwards, each one grabbing a flying prey from the wheeling flock.