When babies are born, they have a strong desire to suck. This natural sucking reflex happens in two stages.
First, when the roof of your baby's mouth is stimulated and then when you place the mother's breast or a bottle in their mouth, the baby will place the lips over the nipple and squeeze it between the tongue and roof of the mouth.
This sucking reflex allows your baby to get all their nutrients in the first few months of life and is also extremely useful for soothing your baby.
The next stage happens when the baby moves their tongue to the nipple to suck, essentially formula from the bottle.
This sucking reflex allows your baby to get all their nutrients in the first few months of life, and is also extremely useful for soothing your baby.