Dogs are becoming more common in American households. Many dogs are affectionate four-legged family members who spend most of their time playing fetch in backyards and sleeping on couches. These dogs are often perfectly harmless under normal conditions. However, even the smallest, oldest and calmest dogs can become aggressive if they believe their owners are in danger.

Some dogs are also bred and trained to be aggressive. These dogs are also often owned by irresponsible people who do not follow through with the steps necessary to keep other people safe. They ignore these precautions when they take the dog out or people venture onto the property. This puts everyone from mailmen to other dog owners at local parks at risk.

According to WCNC, these and other reasons cause more than 200 dogs in Charlotte to face restrictions. The city believes these dogs might be dangerous and with good reason. The restrictions cover who the dogs can be around and where owners can take them. Unfortunately, several owners do not follow through with the necessary safety precautions.

These animals join this “blacklist” after attacking people, livestock or other pets. The list is specially reserved for dogs whose attacks were so severe that the victims required hospitalization afterward. Death also makes the case even worse.

Even people who become victims themselves may have dogs at home. Because of this, everyone should watch out for signs of aggression in their dogs. According to the ASPCA, aggression falls into several categories. Some of these include territorial, fear, defensive, protective and predatorial.

Once pet owners identify what kind of aggression their dogs may have, they can react accordingly. People who recognize these signs in other dogs may also be able to extract themselves safely from a situation before a dog attacks.