I wonder if it will happen again. Toddlers are learning to have an impact on their world and biting definitely has an impact. Modeling or copying the actions of others is an important and powerful way for toddlers to learn. Unfortunately sometimes the toddlers learn negative behaviors like biting. Any adult who has spent much time with a group of toddlers can testify to the fact that biting is more contagious than chicken pox.
Toddlers have very limited language skills.
Consequently, biting is a way to register a complaint. Some children bite when they are tired or hungry or rushed or when Mom is out of town or when Dad worked late last night. Adults need to be aware of what is happening in the life of the biting child and take action to prevent other children from being physically hurt. Biting is especially likely among those toddlers in group care settings. Even so, biting is not and acceptable behavior and adults must help toddlers control their urge to bite other children.