The Science Behind Snake Yawning: What’s Really Happening

Snakes exhibit a variety of behaviors, some more peculiar than others. If you’re not accustomed to some of their behaviors, we’ll dissect one today.

I’m talking about yawning or what appears to be yawning because the behavior itself could mean a variety of things.

So, let’s look at the snakes’ tendency to yawn to understand what it means.

Overview of a Snake Yawn

The gesture itself looks similar to what humans and other animals due, except the snake may move its mandible in several different ways. No noise will come out, though, and some snakes are capable of opening their mouths to impressive lengths.

The act of yawning is called mouth gaping and can signify several behaviors, intentions, or issues, depending on the case.

So, let’s look into that!

5 Reasons Snakes Yawn – Not Because They are Tired

These are the 5 likeliest reasons why snakes may yawn:

1. Preparing to Eat

Unlike most other animals, snakes swallow their prey whole. No preparation, now chewing, no breaking the food into smaller pieces.

And most of the food they’re ingesting is far larger than the snake’s normal mouth opening. Some snakes, like Burmese pythons, can even consume pigs and deer.

This means that the snake needs to prepare itself before eating the prey. And one way it does that is by dislocating the jaw. The snake can do this due to its unique jaw conformation compared to other animals.

Snakes have mobile mandibles, only connected to the upper jaw via elastic ligaments. This system allows the snake to dislocate the jaw and open its mouth considerably more than other creatures.

All snakes have this ability, and all of them will perform this trademark yawning before getting ready to eat. The difference is that some snakes dislocate their jaws only once they begin eating, while others do it upfront.

2. Realigning Their Jaw

Because the mandible is connected to the upper jaw via nothing more than the ligaments we’ve mentioned, accidents can happen.

The mandible may sometimes dislocate from its place, at which point the snake needs to put it back in. The reptile does that by performing specific lateral and rotative movements, forcing the jaw back into its normal position.

The gesture may look as if the snake’s jaw is broken, but this is normal behavior, and it doesn’t hurt the animal.

3. Gathering Scents

Snakes possess a Jacobson’s organ located on the mouth palate. This organ is responsible for detecting and identifying distinct scent particles from the air. The snake usually catches them by flicking its tongue in and out of the mouth.

The gesture allows the reptile to collect airborne particles and drag them inside Jacobson’s organ. This provides the reptile with additional information about its environment, often allowing the snake to detect an animal’s approach.

Snakes don’t need to open their mouths for that, as they possess a small but distinct opening where the tongues slip in and out even while the mouth is closed.

However, the simple tongue flicking may not be enough in certain situations, as is the case with nighttime hunting. Snakes don’t have very good vision, so they rely on their other senses to navigate through the darkness.

Their potent smell is very useful in this sense, but the snake cannot rely on its tongue alone for that. Instead, it opens its mouth wide to allow more scent particles to reach the mouth palate.

This allows for an improved sense of smell, providing the reptile with additional information about its surroundings.

The smell alone isn’t the only way snakes can navigate in the dark. Their ability to sense vibrations through the soil and air is also vital for navigating the ecosystem with precision.

Then you have many venomous and constrictor species that rely on heat pits to detect the infrared print of their prey. This unique ability works perfectly even in pitch-dark conditions.

4. Health Problem (Mouth Rot)

Snakes are prone to a variety of health problems, mouth rot being the most notorious one. Mouth rot is a bacterial infection that affects the snake’s mouth and respiratory system and is the result of poor environmental conditions.

Mouth injuries during feeding or fighting can also become infection points for the bacteria to colonize and use as entry points into the snake’s organism.

Mouth rot is a dangerous condition that can trigger additional health problems if not treated. The affected snake will exhibit a variety of symptoms, the distinct and wide yawning being one of them. Snakes affected by mouth rot yawn to relieve some of the local discomfort.

Other noticeable symptoms include lack of appetite, lethargy, visible stress, and white growths around the mouth, nose, and eyes.

If your snake pet shows signs of mouth rot, you need to consider a viable treatment asap.

This condition is progressive and contagious and can spread to other pets in poor containment conditions.

5. Defensive Display

Snakes are shy and reclusive animals that prefer to live solitary lives. They don’t like confrontations and are rather antisocial and defensive. Most snakes will exhibit aggressive behavior if cornered, scared, or held against their will.

In this case, they will hiss, posture up, attempt to flee, and even open their mouths in a display of aggression.

If all of these warning shots miss, the snake will eventually bite as a last resort. It’s important to respect the snake’s behavior, both in the wild and in captivity. The snake will stress out when scared or threatened, which can impact its health in the long run.

Not to mention, you don’t want to be bitten anyway. Not by a venomous species and not by a non-venomous one, either.

Even if the snake has no venom, it doesn’t mean that the bite cannot cause skin wounds that come with a noticeable risk of infection.

Do Snakes Yawn When Tired?

No, they don’t. Many animals, including humans, tend to yawn because their bodies produce too much CO2. The act of yawning eliminates the excess CO2 and reoxygenates the body properly. Snakes don’t have this problem, though.

This means that they perform ‘fake’ yawning, which has nothing to do with being tired.


Snake yawning can get quite scary, especially if you’re looking at a venomous snake’s gaping mouth. Venomous snakes showcase their fangs when yawning, as these are generally glued to the mouth palate when the mouth is closed.

They will face down as the snake opens its mouth, which allows the snake to bite into whatever requires biting at that moment in time.

So, if you notice the snake yawning, despite not having anything to eat, check the animal’s health status and look for anything that may have triggered the gesture. Make sure you’re not the cause, by the way.

Robert from ReptileJam

Hey, I'm Robert, and I have a true passion for reptiles that began when I was just 10 years old. My parents bought me my first pet snake as a birthday present, which sparked my interest in learning more about them. read more...