My opinion is, the dogs can become aggressive, but they are not from the birth. They can be born with inherited tendencies that might, if not controlled, make aggressive behaviour more likely.
If they are insecure, it is always dependent upon, what they believe is happening to them. Theoretically every single
- Dog, who were allowed to exhibit poor behaviour because of their small size often become aggressive
- Dog, who were abused become aggressive out of fear.
- Dog, who were starved often become food aggressive.
- Dog, who were not properly socialized often become aggressive to other animals.
- Kids approach inappropriate way can become aggressive (pulling tail, ears, riding on them
- Lastly, people often push their dog into aggression without realizing it ( not suitable lead, collar/harness, no understanding of dog’s body language)
- and many other …….
As aggression is always a response, usually to a threat, there is no reason why a dog cannot learn alternative responses. If these responses are controlled throughout the dog’s life, starting with breeding from well-balanced parents and continuing with learning good social skills as a puppy, there is no reason why any dog should learn to use aggression inappropriately. If there are some triggers which, causing the aggression, we can train by positive reinforcement to help dog to cope with negative feelings by associated it with something good, what dog likes.
However, some dog breeds were bred for centuries to become protectors and hunters, and those traits are stamped on their genes. This does not mean that every animal in the breed is aggressive, but simply that the potential is there.