Badger: Hey Stinky! Did you know that snakes have the best eyesight of any animal?
Skunk: Stop calling me Stinky! My name's Claude. And why do you think snakes have the best eyesight of any animal?
Badger: Have you ever seen a snake with glasses?
Skunk: No, I guess not.
Badger: See! (rolls around laughing uncontrollably)
So what did we learn from this conversation? Badger jokes are terrible, that's what! But the badger did have a point. We've never seen a snake with glasses. Does that mean that snakes have great eyesight? Of course not! They don't wear glasses, because they don't have ears to hold them up!
Sorry! We know that joke was as bad as the badger's! But it's true. Snakes don't have ears or eardrums like humans have. In fact, this lack of external ears — and observations that snakes don't tend to respond to sounds — led many scientists to conclude that snakes were deaf. This was the prevailing view for many years until scientists began to study snakes more closely over the last 50 years or so.
Since they don't have external ears or eardrums like humans do, snakes can't hear sounds in the same way that we can. However, it's not really correct to say they're deaf. Scientists now believe there are a couple of different ways that snakes may sense or "hear" sounds.
For example, when large animals move, they produce sound waves that travel through the air. Their movements also produce vibrations that travel through the ground. Scientists have found that the skin and muscles of snakes can detect these vibrations in the ground and transfer them to the brain, where they may trigger a response to stay still as a defense mechanism.
But what about those sound waves that travel through the air? Can snakes hear those without ears? Scientists now believe that they can! Humans have tiny bones in the inner ear that are critical to the process of hearing. Snakes have similar structures on the sides of their head connected to their jaw bones.
Scientific studies have shown that skin and muscle tissue transfer airborne sound waves to a tiny bone called the quadrate, which moves back and forth in response to the vibrations. That movement is then transferred to the cochlea, which translates the movements to electrical signals that are then sent to the brain.
Obviously, this system of hearing in snakes is quite different than it is in humans and other animals that have ears. Snakes likely only hear a limited range of low-frequency sounds. As a result, snakes probably don't rely on hearing in the same way that other animals do. Snakes probably depend primarily on other senses.