Aggressive behavior plays a significant role in the fitness of
animals, and it is widespread in the animal kingdom. Animals
use aggression to defend themselves and their progeny from
attack by predators, to fight for females, to feed, and to
maintain the social hierarchy. The study of aggressiveness is
complicated, however, by the fact that aggressive behavior is
not a unitary trait. The first and most influential classification
related to preclinical aggression was proposed by Moyer.(1)
The classification was based on the eliciting stimuli and
included the following types of aggression: predatory (attacks
on prey), intermale, fear-induced, irritable, territorial, maternal
and instrumental aggression.