Aggression in Animals

Although humans exhibit aggression in its most subtle and complicated
forms, other species of animals also manifest aggressive behaviors. Most animals
will fight if they are attacked because self-defense and self-preservation
are inherent in most species. Within their own social constructs, some animals
will attack those outside their group, even those of the same species, although
few animals turn on their own species to nearly the extent that humans
do. Carnivorous animals exhibit aggressiveness in preying on other
animals as food sources, the large overpowering the small, the swift overtaking
the slow, the strong killing and consuming the weak. Most animals also
aggressively defend the areas in which they forage and build their nests or
dens.
The less aggressive species of animals have been domesticated by humans
as sources of food, notably poultry, cattle, and fish. More aggressive animals
are sometimes used in sports such as bullfighting or cockfighting. In these
instances, the animals are taught aggressive behaviors that are not instinctive
in most of them. They are trained to perform, and satisfactory performance
on their parts is rooted in aggression.