What is a Snake "Yawn"?
One day while you’re observing your snake, you watch them stretch their jaws big and wide, and it appears they are yawning! What in is going on here? Do snakes actually yawn?
The Science Behind the "Yawn"
While even yawning in humans is not fully understood, it is generally thought that we yawn to deliver more oxygen to our cells. However, when your snake seemingly “yawns”, they do not do so for the same reasons. Instead, a healthy snake will yawn for two reasons:
Before and after eating
By what we identify as yawning, they are stretching and realigning their jaws in order to either prepare to eat, or to readjust themselves after eating. Your snake may yawn once or even multiple times to reposition their jaw comfortably, which is completely normal. If you’re wanting to capture a good photo of a snake yawn, feeding time is the best opportunity to do so!
To gather air particles The other reason a healthy snake would yawn is to gather a large amount of scent particles to "smell" the air. When they do this, they expose what is called their vomeronasal or Jacobson’s organ, which registers information on the surroundings to your snake. This helps them detect important factors in their environment such as predatory presence, potential prey, and sources of water. By opening their mouth wide, they are able to gather a larger array of information more quickly than if they were to flick their tongue, as we usually see them do. Typically you will see your snake yawn for this reason if something in their surroundings suddenly changed (i.e. taking them out from their enclosure).
When to Be Concerned
Please keep in mind that sick snakes can exhibit what appears to be a harmless yawn, but is really a sign of infection. The difference can be distinguished by the frequency and manner in which your snake appears to yawn. In a healthy yawn, your snake will typically open their mouth just about as wide as they can, perhaps up to three or four times in a row within a short period of time. This is especially common after feeding, as described above. However, in a potentially unhealthy “yawn”, your snake may partially open their mouth several times over the course of the entire day, and continue to do so on a regular basis.
This is a common sign that a respiratory infection may be present, and the snake should be evaluated for other signs of infections such as discharge from the mouth or nose, excess saliva or drooling, stargazing (tilting the head back and upward toward the sky for long periods of time), and lack of appetite. Have you ever captured your snake “yawning”? As an observational experiment, next time you catch your snake in the middle of a "yawn", consider why they're doing so. It's certainly an interesting phenomenon to witness!