Aggression in dogs refers to behaviours displayed by a dog that are intended to cause harm or threat to another animal or person. Dogs can exhibit aggression for various reasons, including:

1. Fear: Dogs may become aggressive if they feel threatened or scared. This is known as fear aggression.
2. Resource Guarding: Some dogs become aggressive when they feel their food, toys, or other resources are being threatened or taken away.
3. Pain or Discomfort: Dogs in pain or discomfort may display aggression as a defensive mechanism.
4. Territorial Behaviour: Dogs may become aggressive when they perceive a threat to their territory or home.
5. Lack of Socialization: Dogs that have not been properly socialized may be more prone to aggression towards other dogs or people.
6. Frustration: Dogs that are frustrated or unable to achieve their goal (e.g., reaching another dog) may exhibit aggressive behaviour.
7. Maternal Aggression: Female dogs may become aggressive when protecting their puppies.
8. Medical Conditions: Certain medical conditions, such as neurological disorders or hormonal imbalances, can lead to aggressive behaviour in dogs.
9. Genetics: Some breeds are more predisposed to aggressive behaviour due to their genetic makeup.

It's important to understand the underlying cause of aggression in your dog and seek professional help from a veterinarian or a certified dog behaviourist to address the issue effectively and safely.

How calm is an aggressive dog?

To calm an aggressive dog means to reduce or eliminate the dog's aggressive behaviour in a way that promotes a sense of peace and relaxation. This process involves identifying the triggers that cause the aggression, creating a safe and secure environment, avoiding punishment, seeking professional guidance, providing training and socialization, using behaviour modification techniques, and, if necessary, considering medication under the supervision of a veterinarian. The goal is to help the dog feel more comfortable and less anxious, leading to a decrease in aggressive behaviours. 

Dog aggression signs:

Signs of dog aggression can include:

1. Growling: Growling is a warning sign that a dog is feeling threatened or uncomfortable. It is important to take this signal seriously and give the dog space.
2. Snarling: Snarling is a more intense form of growling, often accompanied by baring teeth. It indicates that the dog is feeling very threatened and may escalate to aggression if the threat is not removed.
3. Barking: Barking can be a sign of aggression, especially if it is accompanied by other aggressive behaviours like lunging or showing teeth. It is a way for the dog to communicate their discomfort or to warn others to stay away.
4. Lunging: Lunging is a forward movement, often with a snapping motion, indicating that the dog is trying to get closer to the perceived threat. It is a clear sign of aggression and should be addressed immediately.
5. Showing Teeth: Baring teeth is a sign of aggression in dogs. It is a way for them to show their teeth as a warning to others to stay away.

Understanding these signs can help dog owners recognize when their dog is feeling threatened or uncomfortable and take steps to prevent aggression. It is important to seek help from a professional dog trainer or behaviourist if you notice any signs of aggression in your dog.