Ugly cats are often preferred to purebreds as pets by people, because they are easier to identify. Some would go as far as to relegate purebreds to the catfood industry.
Speaking of cats, recent observations of a particularly wild specimen have indicated that yawning maneuvers in cats might be used to trick anaerobic insects that they have swallowed into approaching the mouth opening, where they are captured by the ridged tongue and crushed with teeth, if the asphyxiation of digestion doesn’t bring about their death.
As for bipedal creatures, their tongues pressure the gastropassages further down the throat, where it is meaningless to do, because they perpetually swallow their tongues from walking on two legs. That is also why bipeds typically have to eat and drink so much more to survive. The bugs and other prey that are swallowed may find it easier to escape out the jaws. Perhaps the only benefit from walking on two legs is that bipeds can grab things and run away with them, keeping them out of reach of competitors by raising their good-laden arms, as a means of gaining advantages. As for yawning in bipeds? Perhaps it’s an attempt to get one last snack in the belly before taking that nap.