HORMONES & AGGRESSION

Are there Links between Hormones and Aggression in Animals?

Are there links between Hormones and Aggression in animals?

Introduction

Aggression is the drive that causes animals to fight for priority in order to access the vital resources, including the dominance in space and on the females. Therefore, Aggression is the basis of intra-specific competition. Given the danger that the blood-spattered struggle leads to the contestants, and the resulting disadvantage for the species, natural selection has favoured in almost all cases, methods of struggle that rarely harm the animals. For instance, Ungulates are involved in fighting bumping and pushing off with horns and only accidentally hitting one another on one side, and some fish are involved in impaling fight with fins or holding the mouth and pushing each other. The renunciation of the struggle by escape or behaviours of submission applies in general to stop the aggression of the winner. In nature, aggression is manifested only in animals (Villalon, 2012, pp.949-953).

The main male hormone i.e. testosterone is the hormone of aggression. In hyenas, in which testosterone level in both sexes is very high, and therefore it is difficult to distinguish the sex. Aggression is an intensive emotion that is raised with changes in hormones. High levels of testosterone were found in violent offenders, and also known that the use of androgens, by builders also results in aggressiveness (Tremblay, 2005, pp. 34-54).

Control of aggressive behaviours depends on the level of neurotransmitters, hormones and metabolites. Participation in aggressive behaviours, even without physical contact, leads to large changes in the activity of brain stem monoaminergic nuclei: serotonin and raphe nuclei locus coeruleus noradrenergic. Many of the results show that the aggressiveness is associated with decreased activity of the serotonin in the brain (Veenema & Neumann, 2007, pp.274-85).

Discussion

The body system of animals consists of a series endocrine gland that secretes hormones into the circulation system. These hormones are carried by the blood to target organs, where they perform their duties. The endocrine system and the central nervous system are intimately related, and hormone levels are precisely regulated by feedback systems (Tremblay, 2005, pp. 34-54).

This paper discusses the role of hormones in aggressive behaviour. This study refers exclusively to vertebrates, since the investigation has been greatest in them than in invertebrates. This paper discusses the significance of hormones, and how level of hormones affects species, individuals and sexes, and at what times these levels can be altered and why (Villalon, 2012, pp.949-953).

A single hormone can have different complexes and effects. Furthermore, the levels of the hormone can be influenced by the levels of other, while being influenced by the levels of other than due to the complex control systems using feedback. At the same time, like the hormones influencing the agonistic behaviour, it can also influence the level of hormones and all this must be added that the effects of hormones may be influenced by social context (Tremblay, 2005, pp. 34-54).

Main Hormones and Their Effects

GLAND

PRODUCT (HORMONES)

SOME EFFECTS

1. - Pineal

Melatonin

Regulates the production of ...