I believe you’ve all seen this scene in movies. A new-born baby’s parent look exhausted during the daytime and complain about his or her baby just won’t stop crying at night.No matter what action parent takes, the baby always keeps them awake. In real life, this situation does happen and it happens ALL THE TIME. You can ask your mom if you don’t believe it.
So, why? Why on earth do babies cry all the time at nights? One of the most popular theories is that babies are hungry. But, have you ever given a second thought to this theory? Since babies can not really express their feelings before they gain the verbal ability, it is hard to tell if a baby is hungry or he or she just has a devious plan planed out. For example, babies purposely wake up their parents at night. This concept may sound a little bit crazy at first but if you dig into this theory, you will find logic in it. A study by Harvard University’s David Haig said this ” The baby is delaying the conception of a sibling by keeping Mom exhausted and not ovulating” In fact, we can never tell if babies are born evil, but we can think that babies doing this for his or her own good. First of all, babies who tend to cry more at night are more likely to pass along their genes to the next generation. And this means it fits the evolutionary biology according to the same study. In other words, this means “the drive to wake Mom (or Dad) up is an evolutionary one: Babies that scream and suckle in the wee hours are more likely to survive and have children themselves.”(same study)
On the other hand, we cannot neglect some other factors may lead babies to cry for milk at nights. A study shows that there are some benefits of nighttime feeding. One of the reason for babies crying at time is that babies are born with no established circadian rhythms.They can’t tell if it is day or night time and it takes time for them to develop the sense of time table. Moreover, the study shows that babies do not make that much melatonin by themselves early on. Mothers’ nighttime breastmilk contains great amount of melatonin (Source) . With all these evidences, scientists believe that babies wake up their parents to feed them in order to obtain melatonin and develop their circadian cycles. Despite the benefit from melatonin, other studies show that nighttime breastfeeding benefits also include keeping a mom’s long-term milk production steady and strong and breastfeeding moms actually get MORE sleep than their formula-feeding counterparts.
This is just another topic we can’t really find out the truth in a short time. We could if we set up a long term experiment to study those babies who wake their parents up and those who don’t. However, this experiment seems impractical because of multiple uncertain reasons.