why do fish or other underwater creatures yawn in a similar way to humans? If they breathe through gills shouldn’t yawning be done more by flairing their gills wider instead of opening their mouth?

Question

why do fish or other underwater creatures yawn in a similar way to humans? If they breathe through gills shouldn’t yawning be done more by flairing their gills wider instead of opening their mouth?

In: Biology

Answer 1

I’ve seen a few different cases where fish open their mouths wider than usual:

* After eating, to stretch out their jaws and maybe clear food fragments from their teeth?
* When they smell something, I guess cause they want a bigger breath of it to figure out whether it’s food
* Social signaling to other fish, depending on species…but I’ve only seen this from bettas and cichlids