A baby generally refers to a human child of less than 1 year out of the womb. A newborn, a child of less than 1 month, is often also called a baby. At birth, a newborn is on average 7.5 pounds, but the normal range is 5-10 pounds.

At birth the human infant is totally helpless with no way to move and no ability to speak in an intelligible manner or even make known their wants and needs through any means what so ever. The most that a baby can do is cry, holler or scream to get attention but even then these little ones have no way to actually convey meaning to another human being. Other members of the animal kingdom are born with an instinctual understanding of what they must do and only have to wait until their bodies reach a point where they can achieve their goals. Even those that need to be taught to do such things as fly and hunt still have an instinctual basis from which to begin and quickly reach a state of viability. http://www.ehow.com/about_6327721_animal-instinct-vs_-learned-behavior.html Human babies on the other hand have to learn everything by watching what the adults around them do and by listening to the sounds they make and associating these noises with actions or objects. http://www.naturalchild.org/james_kimmel/human_baby.html

With this understood a human baby’s whole survival depends on its ability to elicit emotional responses in the adults surrounding he or she that will result in the baby’s needs being taken care of and the protection provided to prevent injury or death. With the help of these providers babies can quickly learn what is needed for their continued survival. As the child ages he or she continues to depend on those surrounding them to learn and progress through the stages of life and eventually reach a healthy adulthood. http://www.ehow.com/about_6327721_animal-instinct-vs_-learned-behavior.html

Babies develop quickly and reach significant milestones on a monthly basis. These milestones are for average babies, some babies may progress sooner or later than the time frames listed here.

1 month: Babies become comfortable with their surroundings.
2 months: At 2 months, some babies begin to smile.
3 months: Most babies are smiling at this age and can recognize their parents with a smile.
4 months: Babies at this age begin to sleep longer stretches at night, may start rolling over on their own, and begin to become much more active. They may begin to take some solid foods at this age.
5 months: Babies become more active, developing better skills with the hands.
6 months: Most babies by this age can start eating some solid foods.