Interrupt such harmful behavior immediately; protect the targeted child; affirm for both that this is unacceptable. However, hurtful behaviors are communication so observe to understand what the biter is trying to communicate. Offer group lessons of acceptable alternatives when angry, frustrated, or whatever stimulates the biting: the whole group practices the alternative together. (I found that stomping a foot offered very helpful release!) And all children can practice communicating back a message such as “You hurt me. I don’t like that. Don’t hurt me again”. Take the focus off the perpetrator and empower all of the children for productive communication.