Let me begin by saying that one of the super powers of Babies is their sleeping positions aside their cooing and cute smiling, they are also cuddly and surely could get away with several things grown-ups wouldn't. They are fragile and at the same time immune to some things like body aches and fatigues from sleeping positions, which I want to talk about in this article.
Although, Babies have some of their own health and anatomy problems, they also have pains due to vaccination shots, colic, circumcision, teething, pains from treatments of diseases and so on. Measuring the level of pains in infants is hard and difficult, the only common ways are through changes in vital signs like blood pressure, heart rate, breathing rate, baby's facial expression and behavioral gestures and also the amount of oxygen in their blood are the common ways pediatricians and other health professionals rates pains in babies.
Wondering why they sleep comfortably in any position and adults or even teenagers could dare not try?
Infants do not usually agree with sleeping belly up in their first weeks after birth, but it is vital in developmental processes. Back sleeping infants enable them to develop their motor skills, this helps them to be able to start to crawl and roll earlier, their agility depends on it a their back bones tends to be stronger with that sleeping position.
Reason why babies cry when they are placed like this and eventually when they fold/cuddle up once asleep back to their folding position as it was in the womb. When they get used to it, which is usually less than or a month, then they realise that they could curl into any position from sleeping belly up or down and this means their motor-skills is developing.
Some of the reasons for babies funny sleeping positions
An average newborn comes with certain reflexes, this they develop in the womb. It made them startle themselves awake from periods of sleep, they can't control this phenomenon which is referred to as "The Startle or Moro"
That's why babies, infants could sleep in any position a grown-up dares not try, irrespective of how you lay them to bed for a sleep, they still find some ways to sleep funny, sometimes forming curls or balls raising their bums up in the air, a gift only for babies and not for adults.
Studies also revealed that babies like to sleep comfortably like in the first image(Sticking their booty in the air) because they miss the womb i.e the several months of curling under the rib-cage and these memories still linger on in them, something a fully grown-up man or woman should not try, otherwise he or she might end up being helped out of that position by daybreak!
Sleeping in Adults
Sleeping in grown-ups could be smooth and at the same time be a tragedy, at least for those suffering from acute Insomnia. Depending on which side of the story you fall into, either way; we are not as lucky as babies with sleeping positions because the bones and joints are not completely developed or almost which makes flexibility more hard.
For Adults, the reasons for not getting a good sleeping position are many, one of which is referred to as The Sleep Anxiety. Different thoughts flood your mind at night, bills to pay, Chronic Insomnia, your work(Which might be a pain in the Ass), and several other reasons keeps grownup awake which makes you stay in one too many spots when sleep doesn't come.
Drunkenness could make an adult sleep in any position, but it comes with a heavy price; bruises, pains, severe hangover and sometimes dislocation occurs, these weird sleeping positions is only gifted to the infants of which we all as adults have tasted one time in the past or when drunk(chuckles).