There are many reasons why reflexes are needed (and probably many that we are unaware of). Most are thought to be for early survival. Exploring these reasons can go some way towards appreciating the beauty of Mother Nature.
Some reasons for reflexes can include:
Life inside the womb
Survival and protection reflexes
Primitive reflexes
Life inside the womb. As you are no doubt aware from your baby's movement inside the uterus, they are actively exercising and practising their crawling and walking reflexes. Your baby uses their feet to push off the side of the woman's uterus so they can move about during the pregnancy.
Some believe this movement is an exercise in preparation for eventual walking. Others believe that when the baby feels the resistance on the soles of their feet from the uterine walls, they push off to change position, ensuring they do not become fixed in the one place. It may even be that these reflexes can help the baby move down the birth canal to be born, pushing themselves off the top of the uterus, or using their crawling action.
Survival and protection reflexes. Reflexes are necessary for life outside the womb. They enable the baby's to survive by obtaining nourishment and breathing. The reflexes responsible for obtaining nourishment are the 'rooting', 'sucking' and 'swallowing' reflexes. Protection responses can include 'blinking', 'gagging', 'coughing' and 'sneezing'.
An example of another protective reflex is when a handkerchief is gently placed over a baby's face. He or she will try to brush it away. Another is the automatic response of a baby to turn their head to one side when they are placed on their tummy.
Primitive reflexes. 'Primitive' reflexes are thought to be derived from our early evolution as human beings. They are believed to be related to our primitive need of having to clutch onto parental (ape) fur with both hands and feet.