There are 2 different types of bears, White Bears and Brown Bears. Like Crocodiles, bears are neutral mobs, meaning that they will wander around aimlessly but still deal damage to a player on contact.
 Brown Bears
Brown Bears can be found on the surface area on Terra. They don't attack or follow the player until the player makes contact or hit them.
 White Bears
White Bears can be found on the surface area on Cryo. As its name implies, it is a white variant of the brown bear.