Fear Based Aggression –
Aggression is defined as growling, barking aggressively, snarling (showing teeth), lunging, “nipping” with bruising or serious biting with punctures. Aggression is usually a defensive behavior in response to fear (fear masked as aggression).
Instinctively, animals are continuously aware of the physical space between themselves and other objects in their environment, including other animals, people, equipment and machinery. Animals continuously attempt to maintain what they perceive as a “safe” physical distance between themselves and other objects in their environment.
If an animal is crated, leashed, or positioned in a manner that makes it difficult for the animal to retreat, he may feel the need to protect himself, and respond with a “fight or flight” response behavior.