Hormones and Aggression in Female Mammals

Floody, Owen R.

doi:10.1007/978-1-4613-3521-4_3

Cited by 43 publications

(29 citation statements)

References 133 publications

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“…In the case of grazing herbivores, it is often assumed there is very little ''interference feeding competition'' between females, as food resource quality is expected to show little variation (Van Schaik 1989). Generally, it is indeed in the female sex that aggression is less forceful (Smuts and Smuts 1993;Floody 1983). This should result in measurable differences in the quality of dominance relations.…”

Section: Introductionmentioning

confidence: 99%

Aggression and dominance in matched groups of subadult Icelandic horses (Equus caballus)

Vervaecke

Stevens

Vandemoortele³

et al. 2006

J Ethol

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We studied sex differences in the nature of aggression and dominance behaviour in two newly formed groups of 1-year-old Icelandic horses. One herd contained nine geldings, the other nine mares. The groups were matched with regard to dominancedetermining traits such as age, weaning age, composition of native herd, social experience, genetic origin, body condition and maternal dominance status. Highranking individuals of both sexes were more aggressive, high-ranking males were older, and high-ranking females had a better body condition. Frequencies of aggressions were similar in both groups. The mares reacted significantly more by showing submission upon an aggression rather than by not responding or by escalating the aggression. For the geldings, this difference was not observed due to a lower tendency to submit. A linear dominance hierarchy was found in both groups. David's scores provided additional information regarding cardinal rank distances and were used to calculate steepness of hierarchies. The female hierarchy was somewhat steeper compared to the male hierarchy, suggesting somewhat lower despotism among males. This was mainly a consequence of the lower unidirectionality in male submission. Male contests occurred predominantly between dyads at top and mid positions, suggesting a low degree of acceptance of the hierarchy.

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Section: Introductionmentioning

confidence: 99%

Aggression and dominance in matched groups of subadult Icelandic horses (Equus caballus)

Vervaecke

Stevens

Vandemoortele³

et al. 2006

J Ethol

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“…Individual differences in the expression of aggression might be related with several behavioral or adaptive characteristics. In support of the aforementioned, it has been shown that dominance might be based on individual skills during competition and not necessarily the age hierarchy within the social group [4][5][6][7][8][9][10].…”

Section: Discussionmentioning

confidence: 99%

“…Studies on mice reveal that grouping adult male mice in cages can result in increased aggression, and could as well reflect a pattern in the social order of dominance [2][3][4][5][6][7][8][9][10][11][12][13]. When a group of monkeys of different sizes were merged and the social order of dominance was observed, some small animals were aggressive and constantly challenged the authority of bigger animals in the social structure, while some were placid and did not challenge the bigger animals [14].…”

Section: Introductionmentioning

confidence: 99%

Integrative focus on dynamic motor patterns and age hierarchy in the expression of aggression

Nathaniel¹,

Aremu

Femi³

et al. 2007

Open Life Sciences

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Abstract:In this study, we analyzed the dynamic motor patterns of attack or defense and age hierarchy to investigate aggression in African mole-rats Cryptomys foxi and the house mouse Mus musculus. The objective is to verify if the social order of dominance is associated with age hierarchy within the social group. Using the resident-intruder experimental model, we created a series of dyadic encounters that comprised of a standard adult mouse or rat paired with groups of aggressive and hierarchically age-ranked small animals in a territorial aggression test. Our results indicate that though the adult animals displayed the highest level of aggression, indicating their dominant status, there was no age-related hierarchical formation in the expression of aggression. In the non-territorial aggression test in which rats or mice were grouped together, animals displayed low levels of aggression compared to the territorial test and no hierarchical age-related order. These results indicate that the magnitude of aggression expressed by animals in the social group, based on their motor patterns of attack and defense, seem to depend on individual competitive strategies in reaction to various environmental challenges and not necessarily on age hierarchy.

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“…Large body size, aggression, dominance, and rough play have all been linked to elevated levels of androgen in other mammalian species (Wade, 1976;Beach et al, 1982;Goy et al, 1988;Monaghan and Glickman, 1992). The relationship between androgens and aggression is not simple or absolute, and there are mammalian species in which females are the more aggressive sex, yet exhibit no genital masculinization (Payne and Swanson, 1972;Floody, 1983). Nonetheless, the combination of physical and behavioral traits observed in female spotted hyenas strongly suggests exposure to elevated levels of androgenic hormones.…”

Section: Indexing Terms: Onuf S Nucleus Androgen Spinal Cord Bulbomentioning

confidence: 95%

Sexual dimorphism of perineal muscles and motoneurons in spotted hyenas

Forger¹,

Frank²,

Breedlove³

et al. 1996

J. Comp. Neurol.

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Female spotted hyenas are known for their male-like genitalia, high levels of aggression, and dominance over males, characteristics which are attributed to exposure to elevated levels of testosterone in utero. Although the nervous system of spotted hyenas has not previously been examined, one might predict that neural systems which are sexually dimorphic in other mammals would be monomorphic in this species. Spinal motoneurons which innervate muscles associated with the phallus are located in Onuf's nucleus and are more numerous in males than in females in a wide array of mammals. Onuf's nucleus was examined in adult and neonatal spotted hyenas and, contrary to expectation, was found to be sexually dimorphic in the typical mammalian pattern: Males have significantly more motoneurons in Onuf's nucleus than do females. This dimorphism was correlated with a previously undescribed dimorphism in the relevant target musculature. Specifically, the morphology of the bulbocavernosus muscle is distinctly different in male and female spotted hyenas. Pregnant hyenas were treated with anti-androgen in an attempt to interfere with the actions of androgen during fetal development. Motoneuron number in Onuf's nucleus and the morphology of the bulbocavernosus muscle were feminized in males exposed to anti-androgen in utero.

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Hormones and Aggression in Female Mammals

Cited by 43 publications

References 133 publications

Aggression and dominance in matched groups of subadult Icelandic horses (Equus caballus)

Aggression and dominance in matched groups of subadult Icelandic horses (Equus caballus)

Integrative focus on dynamic motor patterns and age hierarchy in the expression of aggression

Sexual dimorphism of perineal muscles and motoneurons in spotted hyenas

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