Why do babies cry?

I frequently find myself with reason to wonder about the reason why babies cry. Obviously, I understand that it is their only way to communicate that their needs are not being met. But sometimes the baby is fed, changed, winded, rested, at the correct temperature, entertained and cuddled, and yet they still cry and cry. 

From an evolutionary perspective it just doesn't make sense to me. Surely a baby crying for no apparent reason than cannot be soothed is only drawing the attention of unwanted predators? 

I found a very interesting article from The New York Times - A Darwinian Look at a Wailing Baby.  

It's a great article and summarises the thoughts of several scientists. It's obvious, but something that particularly stood out for me - the odds of an infant surviving to adulthood go up if it gets a lot of food, protection and care. Therefore natural selection should in fact favour genes for the noisier children because they will get more attention.

So it seems that although a louder baby would be easier for predators to find, a quiet baby would be ignored or passed over in favour of others, and therefore not have its needs met and risk not reaching adulthood. The benefit in alerting parents that one's needs are not being met therefore outweighs the disadvantage of being a potential advertisement to predators. 

Very interesting, and something for me to think about further as I pace up and down the corridors trying to soothe my own little one!

(Please note that in the picture above Mia has just been fed and changed and is being walked about in my arms, she is crying because she is tired, I didn't make her cry just so that I could take a photo to illustrate the post!)