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194. The yawn


Did you yawn while watching this video? Chances are you did.

We define yawning as the involuntary process of opening the mouth, breathing deeply, and filling the lungs with air. It is a natural response triggered by sleepiness or fatigue in mammals. However, there is nothing in this definition that can be related to fish. Fish breathe through the aid of gills, which extract oxygen from water. Thus, they do not breathe in air even if they open their mouths. There are also no indications that the so-called yawn occurs involuntarily in fish. Researchers cannot explain why it occurs in humans, making it even more challenging to explain why it occurs in fish.

What we do know for sure is that yawning can be very contagious. This means that if someone witnesses another person yawning, it might trigger a yawn in the observer. Scientific studies show that contagious yawning is more common between strongly bonded individuals than weakly bonded ones. However, if the yawn of a fish, which is neither a human nor a mammal, can penetrate our subconscious mind, there must be something else at play here: the influential power that film has on our brains.

Many underwater videos and marine wildlife films feature yawning fish, and I was never triggered into yawning when watching these works. The combination of visual and auditory stimuli in these underwater videos contributes to the contagious nature of yawning. Why is it that when we watch this short clip, most of us will yawn? There are four different factors that will persuade your unconscious brain to go into “yawn mode.” First, we see a fish yawning on the screen. Secondly, it is accompanied by the stretching sound of its jaws. Thirdly, the yawn sound follows. The fourth trigger is the soothing background music, and finally, the fifth and last part consists of the repetitive imagery sequences of multiple fish species yawning one after another. The combination of all these five factors will probably trigger a yawn in the viewer. Of course, the likelihood of yawning while watching this underwater video is also increased when the person is tired.

Why fish yawn is not fully understood, and maybe it is not because it looks like a yawn that it is a yawn. A more in-depth explanation into the dynamics of a fish’s yawn has been published in some older posts in this vlog. In this latest underwater video, we combined several specimens featured in our other yawning underwater videoclips, as we thought it was a good idea to focus on a fish behaviour aspect rather than on a specific fish species like in most of our marine wildlife videos.


Capturing a yawn on camera is always exciting for the underwater videographer, as it is not always evident to do so. Although fish are the actors of the underwater documentary industry, they are wild animals that can’t be ordered to exhibit a certain behaviour. Patience, in combination with a little luck and the ability to see or predict when a yawn is imminent, will contribute to nice underwater video footage of yawning fish. How to recognise when a yawn might occur is also explained in our previous post about yawning fish.

More posts about yawning fish:

Please visit vlog posts 100 for more on a yawning Lionfish or click here https://www.beyondscuba.com/post/yawning-lionfish

and vlog posts 124 for more on a yawning Rhinopias or click here https://www.beyondscuba.com/post/a-weedy-scorpionfish-rhinopias-frondosa-yawns

and vlog posts 180 for more on a yawning flounder or click here https://www.beyondscuba.com/post/yawning-peacock-flounder-bothus-mancus

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