Alligators move lungs to dive, roll in water

By Julie Steenhuysen

CHICAGO (Reuters) - Alligators can stealthily maneuver through the water leaving nary a ripple, despite having neither fins nor flippers like other adept swimmers. Instead, they use special muscles to shift the position of their lungs, U.S. researchers said on Thursday.

They said American alligators use their diaphragm, pelvic, abdominal and rib muscles to change their center of buoyancy, forcing the lungs toward the tail when they dive, toward the head when they surface, and sideways to roll.

"What this does is it gives the animal a way to change trajectory," said T.J. Uriona, a doctoral student at the University of Utah, whose study appears in the Journal of Experimental Biology.

"It allows them to quietly change how they are positioned in the water so they can strike," he said in a telephone interview.

"This doesn't require any really quick movements that might give their position away."

Uriona and colleagues think this adept manipulation of special muscles to control buoyancy may be important to other aquatic animals, including African clawed frogs, some salamanders, turtles and manatees.

"It might be more widespread. It's not just unique to crocodilians," Uriona said.

Uriona said the research offers a different theory on why alligators have diaphragm muscles, which are not common among reptiles.