Chelonians can make sounds by swallowing or by forcing air out of their lungs, and some species emit unique noises. The red-footed tortoise (Chelonoidis carbonaria), a South American species, makes a series of clucks that sound like a chicken. Male Travancore tortoises (Indotestudo forstenii) in Southeast Asia emit a high-pitched whine that sounds like an electric motor when they're seeking mates. The giant musk turtle (Staurotypus salvinii), which is found in Central America, is known for yelping like a dog when it's startled or being attacked.

But the weirdest sound is made by nesting female leatherback sea turtles (Dermochelys coriacea), who make a distinctly unladylike noise that resembles a human belching, according to the book Turtles: An Extraordinary Natural History 245 Years in the Making.