Discovery Science: Biology – Ethology – Agonistic Behavior

Earth Science: Biology – Ethology – Agonistic Behavior

The powerful clash of antlers or the sight of bared, sharp teeth: these dis- plays of aggression are an important part of the animal kingdom. A complex interplay between aggression and submission keeps animal life in balance.

The ethological term agonistic behavior includes any social behavior related to fighting and covers all types of behavior in response to negative influences from other organisms, including aggression and subordinance.

Agonistic behavior assists animals in securing essential needs such as habitat and territory, food, and sexual partners. It includes two opposite components: aggressive and defensive behavior. The former can involve displaying, threatening, or attacking. Typical defensive behavioral patterns include placation, submission, and escape behavior.

Inter- and intraspecific aggression

Aggression is the willingess to threaten or attack in response to external cues. Intra-specific aggression is targeted at individuals within the same species (conspecifics) while interspecific aggression targets individuals of other species.

Aggression between different species includes predation or antipredator tactics. Intraspecific aggression occurs to secure subsistence needs such as food.

Aggression control

Fights are usually preceded by displays and threatening behavior. A common tactic to appear more threatening is to make the body seem larger by increasing its visual outline, for example, by straightening the body, raising the tail, and bristling the fur.

This can be accompanied by acoustic threats, such as growling. If threats escalate to a conflict situation, fight or flight responses will result in either an attack or escape out- come. However, threatening displays are usually sufficient to diffuse the situation. A stronger animal is less likely to fight if the other animal displays submissive behavior (for example, lowering the tail).

Pacification behavior may also inhibit the victor from killing, which is important for a species as a whole. Serious fights may lead to grave injuries or death, while ritual fights, usually preceded by extended threat displays, tend to cause little or no injury. The latter have fixed rules and are usually carried out to secure or improve an animal’s social rank. Serious injuries in this case are rare.


Many vertebrate groups are organized by rank, determined by fights among rivals. This system ensures that the group is guided by a strong and experienced lead animal. Rank order largely prevents intraspecific fights for food, mating partners, and so on.

Animals of higher rank often have a better chance of reproduction than low-ranked animals. Rankings are usually dynamic and reorganized after regular fights for position.


TERRITORIAL behavior is a form of aggression through which territory is defended against conspecifics.

Boundaries are set by marks, or acoustic or optical signals.