Underwatertimes.com News Service - December 12, 2005 00:00 EST

Researchers in Belize using electronic tagging on whale sharks have finally solved a marine mystery and discovered where the sharks find food.

Scientists say the 65-foot-long whale sharks -- the world's largest fish -- dive nearly a mile in search of food.

The new insight into whale shark behavior is the result of research conducted at the Belize Barrier Reef, the world's second largest barrier reef system, the BBC reported Monday.

Our study showed that sharks dive much deeper than previously believed, reaching depths of over 1,000 meters (3,300 feet) in search of food, said Rachel Graham of the U.S.-based Wildlife Conservation Society.

Water that deep is only a few degrees above freezing and that explains why tropical whale sharks have an insulating layer of fat just below their skin -- a fact that has puzzled scientists for years.

The electronic tags the scientists attach to the fish record temperature, water pressure and light level and then beam the data back via satellite, the BBC said.

The findings appear in the Royal Society's journal Interface.