Snakes Hear With Their Jaws—Here’s How That Works

Since snakes do not have external ears, humans often make the mistake of thinking they cannot hear. Snakes do not even have small ear openings on the sides of their heads like lizards and crocodilians. However, snakes are far from deaf. Although snakes do not hear the same way as humans or other reptiles, they can certainly hear — and they use their jaws to do so. Keep reading to find out how.

It’s What’s Inside That Counts

Although snakes lack external hearing mechanisms, they have a complete inner ear structure. This structure houses the cochlea, which, in both humans and snakes, transforms sound vibrations into nerve impulses that the brain perceives as sound. However, instead of three bones in their middle ears like mammals, snakes have a single modified bone called the columella. The columella is connected to the quadrate bone, which suspends the snake’s lower jaw from its skull.

Snakes “hear” by detecting surface vibrations with their jaws. When snakes rest their jaws on the ground, they can detect extremely subtle, low-amplitude minute vibrations. These vibrations travel from the bones of the lower jaw to the columella and into the snake’s inner ear. Scientists believe the cochlea stimulates the snake’s brain to create a neural map of its surroundings, which allows the snake to determine the direction of the sound.

Snakes can also use their jaws to hear “in stereo.” The quadrate bone gives the snake’s lower jaw extraordinary flexibility. Snakes can move their jaws both horizontally and vertically, which enables them to swallow large prey. Because the right and left sides of a snake’s lower jaw are separated, each side can receive vibrations independently, giving the snake a form of stereo hearing.

Snakes Can Hear More Than You Think

Recent research suggests that snakes can detect not only ground vibrations but also airborne sounds. Scientists previously believed that snakes only reacted to low-frequency sounds that created distinct ground vibrations. For example, royal pythons were found to respond best to sounds between 80Hz and 160Hz.

However, experiments have shown that snakes respond to airborne sounds at frequencies of up to 450Hz. Researchers found that sounds traveling through the air can cause enough vibration in the snake’s bones for the snake to detect them. Since the fundamental frequency of human speech lies between approximately 80Hz and 300Hz, some scientists believe that snakes can even hear humans talk — or scream.

Other Ways of Hearing

Snakes have more than one way of hearing. Additionally, not all snakes live on the ground. Aquatic snakes and arboreal snakes have also been shown to respond to low-frequency sounds. So, how do these snakes hear? A snake can also perceive both airborne and ground-based vibrations through the surface of its body, a process known as somatic hearing.

Researchers believe that somatic hearing likely originates in the mechanoreceptors in a snake’s skin. Mechanoreceptors are sensory receptors that detect mechanical stimuli. Depending on the snake species, these sensory receptors can be concentrated on different parts of the body. For example, in aquatic snakes, their mechanoreceptors are primarily described as being distributed over their heads. However, in blacksnakes and other species, vibration-sensitive nerve endings have been found along the entire length of the snake’s body.

The auditory pathway for this type of “hearing” remains poorly understood. However, researchers believe that snakes’ ability to consistently respond to sound vibrations with predatory or defensive behavior suggests that hearing may be a more important sensory component than previously realized.

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