It's the normal way for them to communicate.
Studies show the average newborn cries one to three hours each day.
When a baby reaches six weeks of age, most will increase crying to two to four hours a day. By 10 weeks, most babies learn other ways to communicate with you and begin to quiet down and cry less. When your baby cries, try to determine the reason. The baby will not be spoiled if you pick him or her up. An infant who is picked up, cuddled and soothed is learning about forming a loving relationship, an important developmental lesson.