Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more . Summary Scientists have recorded rig sharks producing sounds by snapping their teeth, a groundbreaking discovery in shark communication. The clicks, similar to popping balloons, last about 48 milliseconds and reach 156 decibels. Researcher Dr. Carolin Nieder first noticed clicking during behavioral training experiments at the University of Auckland.