Ethology Aggression

male elephant seals fighting

ethologists study aggression relates interaction , evolution of animals in natural settings. in such settings aggression can involve bodily contact such biting, hitting or pushing, conflicts settled threat displays , intimidating thrusts cause no physical harm. form of aggression may include display of body size, antlers, claws or teeth; stereotyped signals including facial expressions; vocalizations such bird song; release of chemicals; , changes in coloration. term agonistic behaviour used refer these forms of behavior.

most ethologists believe aggression confers biological advantages. aggression may animal secure territory, including resources such food , water. aggression between males occurs secure mating opportunities, , results in selection of healthier/more vigorous animal. aggression may occur self-protection or protect offspring. aggression between groups of animals may confer advantage; example, hostile behavior may force population of animals new territory, need adapt new environment may lead increase in genetic flexibility.

between species , groups

the apparent type of interspecific aggression observed in interaction between predator , prey. however, according many researchers, predation not aggression. cat not hiss or arch when pursuing rat, , active areas in hypothalamus resemble reflect hunger rather reflect aggression. however, others refer behavior predatory aggression, , point out cases resemble hostile behavior, such mouse-killing rats. in aggressive mimicry predator has appearance of harmless organism or object attractive prey; when prey approaches, predator attacks.

an animal defending against predator may engage in either fight or flight in response predator attack or threat of attack, depending on estimate of predator s strength relative own. alternative defenses include range of antipredator adaptations, including alarm signals. example of alarm signal nerol, chemical found in mandibular glands of trigona fulviventris individuals. release of nerol t. fulviventris individuals in nest has been shown decrease number of individuals leaving nest fifty percent, increasing aggressive behaviors biting. alarm signals nerol can act attraction signals; in t. fulviventris, individuals have been captured predator may release nerol attract nestmates, proceed attack or bite predator.

aggression between groups determined partly willingness fight, depends on number of factors including numerical advantage, distance home territories, how groups encounter each other, competitive abilities, differences in body size, , territory being invaded. also, individual more become aggressive if other aggressive group members nearby. 1 particular phenomenon – formation of coordinated coalitions raid neighbouring territories kill conspecifics – has been documented in 2 species in animal kingdom: common chimpanzees , humans.

within group

aggression between conspecifics in group typically involves access resources , breeding opportunities. 1 of common functions establish dominance hierarchy. occurs in many species aggressive encounters between contending males when first in common environment. more aggressive animals become more dominant. in test situations, of conspecific aggression ceases 24 hours after group of animals brought together. aggression has been defined viewpoint behavior intended increase social dominance of organism relative dominance position of other organisms . losing confrontations may called social defeat, , winning or losing associated range of practical , psychological consequences.

conflicts between animals occur in many contexts, such between potential mating partners, between parents , offspring, between siblings , between competitors resources. group-living animals may dispute on direction of travel or allocation of time joint activities. various factors limit escalation of aggression, including communicative displays, conventions, , routines. in addition, following aggressive incidents, various forms of conflict resolution have been observed in mammalian species, particularly in gregarious primates. these can mitigate or repair possible adverse consequences, recipient of aggression may become vulnerable attacks other members of group. conciliatory acts vary species , may involve specific gestures or more proximity , interaction between individuals involved. however, conflicts on food followed post conflict reunions, though frequent type in foraging primates.

other questions have been considered in study of primate aggression, including in humans, how aggression affects organization of group, costs incurred aggression, , why primates avoid aggressive behavior. example, bonobo chimpanzee groups known low levels of aggression within partially matriarchal society. captive animals including primates may show abnormal levels of social aggression , self-harm related aspects of physical or social environment; depends on species , individual factors such gender, age , background (e.g. raised wild or captive).