The fact that a 3-month-old baby eats his hands frequently means that he has mastered this skill, which is a great sign that mom doesn’t need to worry. Little babies are very interested in their hands, and they may stare at their fingers alone for half a day. They also try hard to get their hands into their mouths, but they are often unsuccessful at first, and later, as they become more capable, they will master this important developmental skill and be able to stick their thumbs in their mouths and eat as long as they want. Next baby will use his hands and mouth to explore the world, you can prepare some easy to grasp toys for baby, wash baby’s hands and toys, give baby a safe and hygienic environment, let him explore to his heart’s content, which is very important for the development of baby’s hand-eye coordination, fine motor skills and so on.