 Dear students, in this topic we shall discuss the agonistic behaviors in animals. The agonistic behaviors are those behaviors which involve confrontation, aggression, threat displays, attacks and fights between animals. Such behaviors are displayed by individuals of many animal species. The reason for such behaviors is the limited resources, that is, limited food, limited shelters and limited mates. The agonistic behaviors are usually used only to intimidate the enemies. They are usually not lethal. There are fights in animals, but they don't kill each other. These behaviors are seemingly, on the surface, these behaviors are anti-social behaviors. But they are still important in maintaining social order, in maintaining the territories and in maintaining the dominance hierarchies. There are two types of agonistic behaviors. First are the territorial behaviors and second are the dominance hierarchies. The territorial behaviors include territorial ownership and defense. To seize a place and protect it, this is territorial behavior. Territory is a fixed area in which an animal spends most of its time. It also protects the area and does not allow any other member of its species to go. The territorial behavior is found in most social animal populations. For example, territorial behavior is found in insects, crustaceans, fishes, amphibians, lizards, birds, mammals and humans in all types of animals. Now we shall discuss the purposes of territorial behavior. The first purpose of territorial behavior is to occupy a defined territory for breeding, as it is the main purpose of male birds and mammals. Males actively defend their occupied area against other males. A male who makes a territory there attracts a female, then performs courtship and mating without interference. Another purpose of territorial behavior is to occupy a territory with abundant food supply. Another purpose is to occupy a territory that provides shelter to the animal from predators and unfavorable climate. Dear students, now we shall discuss the dominance hierarchies. Dominants hierarchies are the organization of groups in such a way that some members of a group have greater access to resources, for example to food and to maids than the others. Some animal groups show dominance hierarchies in which some individuals are considered at the top of the order. Some members are considered at the top of the order and they have the first choice of resources. Those members who are at the bottom of this hierarchy do not get sufficient access to resources. This is how hierarchies exist in many vertebrate groups.