The reason is that your toddler is realising that he or she has an impact on the world around them, and they are struggling to exercise this kind of autonomy. Often, they cannot yet articulate their desires, which lead to frustration, and to your child ‘acting out.’
Hitting and biting in children this age is also normal, and is more about getting a reaction than about a desire to inflict pain. At this age, your child does not understand that their actions can cause others pain.
In most instances, the best response to a temper tantrum or some other form of misbehaviour is to remain calm, and to discuss the matter with your child when they’ve calmed down.
Temper tantrums and bad behaviour are completely normal for toddlers and young children. In most cases, they will diminish in frequency and intensity by age four or five.