With all the different theories exist about aggression, there still is no conclusive proof available whether or not genuine spontaneous aggression exists. The truth is probably that aggression results from all three processes. Research is available to support all three theories. For our purposes however, we should concern ourselves less with where aggression comes from and more with what triggers it, what its goal is, and what its biological significance is. So, let's deal with active aggression.
Intraspecific aggression is activated by rivals, and by anti-social behaviour.
The goal of the drive is to cause avoidance, submission, or worse of the rival. Biological significance is even distribution of a species over available land to reduce the possibility of food shortages and epidemics. As well as survival of a species and a pack by selecting the fittest animals for reproduction and as leaders. In species with a social hierarchy behaviours developed from the aggressive drive, which limit the negative results and guarantee the positive results of social aggression such as threatening, dominance, submission, and rituals of non-physical combat. Aggression increases through maturation and practise.