September 11, 2006—Each year a surprising number of whale sharks—the world's largest fish—are drawn to a coral formation called the Gladden Spit, about 25 miles (40 kilometers) off the coast of Belize (map).

The massive sharks glide into the region at about the same time that smaller fish species congregate by the thousands to reproduce. But adult fish have no reason to fear—whale sharks are filter feeders, meaning that they usually feed on tiny ocean plants called plankton.

Watch as a pair of divers take in the action near a column of spawning dog snappers, and witness the biologists' amazing discovery as a whale shark emerges from the milky waters to feed on what could be called the freshest fish in the sea.