According to a Reuters report, British researchers have used “4D” scans to show that fetuses yawn in the womb. As you can see above, the fetus opens it mouth long enough and in such a fashion that it can be distinguished from other types of mouth opening.
Scientists aren’t sure yet what the importance or function of yawning is for fetuses, but they think it indicates good health and has to do with the maturation of the brain.
I just googled “4D” and apparently it is a classification of the Selective Service System, a psychedelic drug, a train in Melbourne, Australia, and an episode of The X-Files in addition to being the type of scan they did.
Scientists have not commented on whether or not the fetuses’ yawning constitutes a fairly blatant display of existential ennui.