for National Geographic News
It's a quiet Friday morning on the Suwannee River in northwestern Florida, when a giant fish suddenly leaps six feet (two meters) out of the water and crashes back into the river.
The stunt is performed by a Gulf sturgeon, a giant fish that traces its roots back to the days of the dinosaurs and can grow up to 8 feet (2.5 meters) long and weigh up to 200 pounds (91 kilograms).
Every few minutes over the next hour, more sturgeons reproduce the feat.
Why the sturgeons jump has been the topic of a long-standing debate. Some scientists have suggested they do it to avoid predators; others have proposed that they do it simply for fun.
(Read related story: "Giant Jumping Sturgeon Stir Up Mystery in Florida River" [August 17, 2006].)
Ken Sulak, a biologist at the U.S. Geological Survey in Gainesville, Florida, thinks he has found the answer.
The sounds jumping sturgeons make are distinct from the sounds of other jumping fish, Sulak says. He believes the jumping is a form of communication that sturgeons use to connect with larger groups and maintain community cohesion.
"I think of sturgeon-jumping sounds as being equivalent to cows mooingannouncing to the larger group the presence and position of individuals," Sulak said.
"Still Get a Thrill"
A subspecies of the Atlantic sturgeon, Gulf sturgeons are found in the coastal rivers of the Gulf of Mexico. The Suwannee River, which runs from southern Georgia through northern Florida, contains the largest population of Gulf sturgeons.
(See an interactive map of the Suwannee River.)
According to one 2001 estimate, between 5,500 and 7,650 adult sturgeons live in the Suwannee.
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