By Stacey Venzel
Even though turtles do not have vocal chords, they still communicate with sound. But sound is not the only way they send a message.
These animals prove that words are not the only way to send information. Using their five senses, turtles talk to to each other and to other animals, sometimes using communication as a form of defense and trickery.
Sound is the most obvious form of communication, and while turtles do not talk, they still speak using other noises. Male travancore tortoises send out a high-frequency whine when mating. The freshwater big-headed turtle is known to make a roaring sound when pulled onto land, supposedly to deter attackers. Arrau turtles are believed to use echolocation to navigate the murky waters of the Amazon River.
Vibrations are a form of communication among turtles. In a phenomenon called titillation, water vibration is used in mating rituals among species. Noted in chelonians with long claws, including painted turtles, rapid shaking of the feet tells a female a male is ready to mate. Male gopher tortoises routinely pound their plastrons on the ground outside of a burrow, calling the females up from below for mating.
Coloration and gestures can signify certain information in turtles. Bright colors like those in snake-necked hatchlings act as warning signs to predators. Without actually biting, alligator snapping turtles can scare off predators simply by opening their mouth, suggesting a devastating bite. Steady blinking patterns observed underwater in female sliders positioned face to face with males seemed to suggest courtship acceptance.
Silent communication also extends to the nose for mating and evading predators. A number of turtle species have scent glands and sniff the opposite sex to find out if it is ready to mate. The common musk turtle is actually nicknamed the “stinkpot” because it makes itself smell bad in order to avoid capture.
Because smell and taste are related, a bad-smelling turtle is a bad-tasting turtle. Snake-necked hatchlings not only have warning colors but also emit a foul odor, and catfish have been noted spitting them out. A peeing or pooping turtle is also not a tasty meal, so some species tell a predator to back off this way.
Carl J Franklin, Turtles: An Extraordinary Natural History 245 Million Years in the Making (St. Paul, Voyageur Press, 2007), 23, 32, 40.
Whit Gibbons, Judy Greene, Turtle: The Animal Answer Guide (Baltimore, The John Hopkins University Press, 2009), 31, 37-39.