Why do young children bite?
The biting may be a normal developmental phase for infants and toddlers, with virtually no long-lasting developmental significance.
Infants
For infants, developmental theorists suggest that biting is probably a form of exploration–infants use their mouths to explore because it is one of the most developed parts of their bodies.
Toddlers
As with infants, biting in toddlers between 12 and 36 months old is a form of communication (i.e., to communicate frustration while learning social, language, and self-control skills).
Preschoolers
Occasional or rare biting from preschoolers may occur for some of the same reasons as it does for infants and toddlers–to exert control over a situation, for attention, as a self-defense strategy, or out of extreme frustration and anger. Frequent biting after a child turns 3, however, may indicate other behavior problems, because by that time many children have the communication skills necessary to relate their needs without biting.

