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Why Do Snakes Yawn? (The 4 MAIN Reasons)

As humans, we have a tendency to explain cute or wacky animal behavior by anthropomorphizing animals. To anthropomorphize something, it means to apply human characteristics, behaviors, or feelings to an animal (or object). In this case, saying a snake is yawning because it is sleepy is certainly an example of anthropomorphizing. So then, why do snakes yawn? That’s exactly what we’ll find out in this article. 

Since have no idea how snakes experience tiredness, we can’t assume that a snake yawning means that the snake is actually tired. In fact, a snake opening its mouth in a yawning fashion has several other biological explanations that are not related to the snake being tired or sleepy. The more accurate term for this behavior is mouth gaping. Now that we’ve got that definition out of the way, we can dive into some of the real reasons why snakes yawn:

Why do snakes yawn? Here are the 4 main reasons

1. To detect chemical cues

If you have ever watched a snake, you have probably noticed it tongue flicking, or repeatedly sticking its’ forked tongue out and bringing it back in. This is because snakes use chemical cues, or scent particles to learn about their environment.

At the roof of a snake’s mouth is a sensory organ called the Jacobson’s organ, which helps to interpret information about the snake’s surroundings. During tongue flicking, snakes will stick their tongue out and bring it back in after having picked up scent particles that make contact with the Jacobson’s organ.

In addition to tongue flicking, mouth gaping (or yawning) is another way for snakes to allow those scent particles to make contact with the Jacobson’s organ. Snakes rely heavily on chemoreception which is essentially their sense of smell. Mouth gaping allows for these scent particles to come into contact with the Jacobson’s organ. By mouth gaping and picking up chemical cues, snakes can detect potential prey items, threats, or other snakes near-by. 

2. To adjust its jaws before and after a meal

Even people with very little to virtually no knowledge of snakes know that snakes swallow their prey whole. Unlike mammals, snakes do not need to chew their food to enjoy a meal. And as vertebrates with bones they have jaws that have evolved to allow them to consume prey items whole. 

One common myth is that snakes unhinge their jaws. This is not true. Instead, snakes have an upper jaw and a lower jaw that is made up of two parts that move independently of each other. The lower jaw segments are attached to each other by very elastic ligaments that allow for their jaws to spread out. This means that snakes can eat animals that are much larger than their mouths. 

While swallowing their prey, snakes will “walk” their jaws along their meal. The segments of the bottom jaws will move separately to help slowly engulf their meal. This process can take several hours depending on how big the meal is. 

Snakes stretch for large meals

Just as you would stretch out your legs before a long run, snakes may also stretch out their jaws before eating a large meal. Often snakes will wait for their prey to be dead, or nearly dead before beginning to chow down.

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So, whether this means a venomous snake bites its prey and waits, or a constricting snake waits for its meal to stop moving before beginning to eat, snakes may take the extra time to prime their jaws for swallowing their food. So you may see a snake yawning just before they are ready to start consuming their food.

As well as after large meals

Snakes may also need to adjust their jaws after eating. As you can imagine, spending up to several hours with your jaws spread open as wide as they can go, might require some stretching and readjusting afterwards. Because the bottom jaw has two independent segments, snakes may need to yawn or gape their mouths open to help adjust their jaw so that these two bottom segments are aligned with each other. 

If you have ever seen a snake just after eating, you may have noticed that the bottom jaw looks lopsided. This is because the snake hasn’t had a chance to properly adjust its’ jaw back to normal. It looks pretty goofy and I can’t imagine it’s very comfortable for the snake. 

You can probably tell if a snake is adjusting its jaws through mouth gaping before or after a meal depending on whether or not you can see a visible lump in its stomach, suggesting that it has just eaten. 

3. Sickness or infection

Snakes have nostrils that they breathe through (like us) as well as an epiglottis. The epiglottis is an opening at the back of the snake’s mouth that opens up into the snake’s trachea or windpipe. The epiglottis is used to create the iconic hissing sound that snakes make, but it also helps snakes breathe. 

Snakes can get respiratory infections like humans which can complicate their breathing. In these cases, where snakes aren’t able to breathe air comfortably through their nostrils, snakes may yawn or gape their mouths in attempt to get air through their epiglottis. This is similar to how when we have colds that produce lovely mucus and give us a stuffy nose, we tend to need to breathe more through our mouths. 

Respiratory infections tend to affect captive snakes more than wild snakes due to the fact that captive snake enclosures tend to have less airflow than out in the wild. Making sure that enclosures are clean and have proper circulation is very important for keeping captive snakes healthy.

However, if you think that your pet snake is excessively yawning or mouth gaping due to an infection or some other sort of illness, there are several other symptoms that you should look out for that tend to accompany mouth gaping. Things you should look out for include weight loss, abnormal stools, regurgitating (essentially throwing up), lethargy and decreased appetite or desire to feed. 

4. Simply just stretching

Depending on the species, snakes tend to sit still for long durations of time. Sitting still for an extended period can make muscles stiff, and that includes the muscles and ligaments that are attached to the jaws of snakes. Snakes may mouth gape or yawn to stretch and alleviate some of that stiffness. It’s not much different than when we’ve been sat down for a long time, say in a car or on a plane, and getting up and walking around can help to loosen up those muscles that have been sat still for so long.

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Snakes yawning or rather, mouth gaping is definitely one of the cuter things that snakes do. It is hard to see snakes as these vicious, blood thirsty animals that people paint them out to be when they are busy stretching and readjusting their jaws that makes them look like their alarm has just gone off. 

Snakes don’t yawn often, and it can be hard to catch them doing it. However, if you have a pet snake that is yawning more than usual or is yawning several times in quick succession, it could be a sign that the snake is sick. If you worry that your snake is sick, it’s important to get your snake to the vet.

If the snake shows no other signs of illness and only yawns every once in a while, then consider yourself lucky to catch them in the act and try to get a picture next time! Everybody loves a good snapshot of a googly eyed snake looking like it has just woken up. 

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