When attempting to distinguish between fear or excitement as the cause of a dog's biting and nipping behavior, there are certain cues that can be observed. Fear-based aggression is often displayed in an animal with its ears back, eyes wide, body low and stiff, hiding behind objects or people, and licking its lips; whereas signs of excitement include barking, jumping up on people, waving the tail, and running around rapidly. Additionally, if the behavior occurs when visitors come over or when new toys/treats are presented, it may indicate that the dog is displaying excited rather than fearful behaviors.