You can determine the baby is hungry through the following aspects: First, the baby will appear to cry when hungry, and is a loud cry, and will have a body writhing before crying, and is increasingly irritable performance, the needs are not met before the loud cry. Second, when the baby is hungry, the small mouth will make sucking action, or sucking fingers, when the parent’s finger touches the baby’s face, the baby will turn his face to make an eager search action, in this case is the signal of the baby for food. Third, a slightly older baby will show happy expressions and actions when seeing the mother coming around or when seeing the parents holding the bottle. Fourth, when the baby eats milk, he or she shows urgency, sucking milk and swallowing eagerly, which means the baby is very hungry.