CBS Sunday Morning – We leave you this Sunday morning with whale sharks near Holbox Island off the coast of Cancun, in Mexico. Videographer: Lance Milbrand.

As the largest fish in the sea, reaching lengths of 40 feet or more, whale sharks have an enormous menu from which to choose. Fortunately for most sea-dwellers—and us!—their favorite meal is plankton. They scoop these tiny plants and animals up, along with any small fish that happen to be around, with their colossal gaping mouths while swimming close to the water’s surface.

Filter Feeding

The whale shark, like the world’s second largest fish, the basking shark, is a filter feeder. In order to eat, the beast juts out its formidably sized jaws and passively filters everything in its path. The mechanism is theorized to be a technique called “cross-flow filtration,” similar to some bony fish and baleen whales.