When you think about turtles, you likely think about their shells and the adage, “Slow and steady wins the race.” What you probably don’t think about is how they hear. But now you might wonder: Do turtles have ears?
The short answer is yes, but they aren’t the traditional ears that you’re familiar with, like a dog’s ears or your own. Turtles have internal ears that are extremely difficult to see.
Read on to learn more about how a turtle’s ears work!
A Turtle’s Ears
Turtles have internal ears rather than the external ears found on most mammals. They have inner and middle ears, but we can’t see these because they are covered with a thin flap of skin. This flap is called the cutaneous plate and is similar to the skin on the turtle’s head.
Turtles also don’t have eardrums like us; small bones in their inner ears help interpret sounds.
How Do a Turtle’s Ears Work?
The shape of a human’s external ear is designed to capture sound waves and funnel them into the inner ear, where the sound is processed and reaches the brain. Interestingly, their inner ear can pick up vibrations felt on their shell; this allows them to “hear” whenever their shell is touched.
Sound waves hit the turtle’s cutaneous plate, which vibrates and sends low-frequency sound waves into the ear canal. The inner ear then processes the sound waves, which are transmitted to the turtle’s brain for analysis.
Turtles seem to have hearing that’s better adapted to working underwater. Their ability to hear sounds in the air (sounds present when they’re out of water) is considered to be inferior when compared to mammals and other reptiles 1.
How Well Do Turtles Hear Underwater?
As mentioned above, turtles hear better underwater than when on land. They can hear frequencies around 500 Hz (rolling thunder can be around this range), which is higher than most other reptiles.
The subcutaneous plate and layer of fat inside their ears become conductors of sound while they’re in the water. The sound travels to the middle and inner ears. Turtles are also sensitive to air and water pressure and can detect changes in water pressure caused by swimming fish or an approaching predator.
Sea turtles hear best at around 200 to 750 Hz and don’t respond to sounds above 1,000 Hz. High frequencies include sounds like birdsong, which can range from 1,000 to 8,000 Hz. The subcutaneous plates allow vibrations in and keep water out.
How Well Do Turtles Hear on Land?
Turtles hear better in the water than on land, but they can respond to changes in air pressure in addition to vibrations. So, they might not hear some birds chirping, but they’ll sense the vibrations of the bird flying nearby.
What Are a Turtle’s Best Senses?
Turtles have all the same senses as other animals, but most of them are sharper than their hearing.
Smell
The turtle’s sense of smell is thought to be their strongest sense. Turtles can smell prey, such as fish and shrimp, even in murky waters.
Like many other animals, they also use their sense of smell on land to select a mate; males and females find each other by smelling their respective pheromones. Their sense of smell additionally helps them to avoid predators.
Sight
Turtles have excellent sight and can easily locate food and avoid predators. They can also detect and tell the difference in shapes, patterns, sizes, and colors.
They can see near-ultraviolet, violet, yellow, and blue-green light. Unsurprisingly, they also see better underwater than on land. Their vision is similar to that of most birds.
Touch
You might think that turtles wouldn’t be sensitive to touch because of their thick skin and shells, but they are surprisingly touch sensitive. Various nerves run along their skin and shell, enabling them to feel when it is touched. This, in conjunction with the inner ear structures, allows them to “hear” where their shell has been touched. This is why it is discouraged to unnecessarily handle pet turtles, as the action can be stressful for them.
Compass (Sort of)
Sea turtles have a kind of internal compass, and sea turtle hatchlings use it to orient themselves after getting through the surf from their sandy nests. They do this by orienting themselves to Earth’s magnetic field. It also enables adults to stay on course while migrating, so sea turtles can navigate wherever they want to go.
How Do Turtles Communicate?
It was long believed that turtles didn’t hear or have vocal cords, so they were thought to be non-vocal, which is not surprising because most people have probably never heard a turtle make any sound.
But a 2022 study found that turtles communicate with quite a diverse range of vocalizations. The most common sound that they make is hissing, which is thought to express fear.
Turtles expressing hostility or a warning tend to hiss and pant heavily, and mating turtles make high-pitched sounds. It’s also thought female turtles emit sounds as a way to communicate with their unhatched young. Sea turtles likely make these sounds to encourage their young to hatch around the same time. Baby sea turtles are picked off quite substantially by predators after hatching, so hatching en-masse helps increase the chances of more hatchlings surviving.
Conclusion
Turtles likely hear more than most people might expect, but their hearing isn’t their strongest sense. They can hear low-frequency sounds and will stop hearing sounds altogether once they hit 1,000 Hz.
A turtle’s ears are internal, with a skin covering them, so it’s difficult to see them, but this enables turtles to keep out water while swimming.
Featured Image Credit: DiPres, Shutterstock
