"Chubby Checker" Frogs

Guess we should expect these critters to show up at the dance platform during the Folk Festival (June 17-20).

By Jeanna Bryner
LiveScience managing editor

One species of male frog shakes its booty big-time in aggressive showdowns, with the victor pulsating its rear for a longer time and with more gusto.

The shaking, which starts with the hind end and becomes a whole-body affair, sends vibrations along the red-eyed treefrog's plant perch until the shaking reaches the frog's opponent sitting on the branch — this process is called tremulation.

"In the case of red-eyed treefrogs, tremulation displays in which the frogs shake their entire bodies convey information about the status and aggressive intent of the signaler," said researcher Michael Caldwell of Boston University. "They also appear to carry information about the size of the signaler."

Scientists had missed the waggling frogs because observations had taken place under white artificial light. "They're nocturnal, so you shine a light on them they say 'daytime,' or 'something is wrong here,'" Caldwell said. That kept the frogs from their normal booty-shaking routines.
But as soon as Caldwell and his colleagues went into the rainforests of Panama wielding infrared lights, the tremulations were apparent.