Turtles don’t have vocal cords and their ears are internal, so scientists believed that turtles were deaf and didn’t communicate through sounds. However, research has found that turtles actually communicate at an extremely low frequency that sounds like “clicks, clucks, and hoots” that can only be heard through a hydrophone (a microphone used underwater). These sounds even come from the egg before the turtle hatches. Researchers hypothesize that this helps all the turtle siblings hatch at once.