Game of Thrones: Scientists decipher patterns of dominating behavior between the sexes in mammals

The stronger, more aggressive gender dominates the weaker gender
.
This simplistic view of the dominant relationship between men and women is widespread, but fails to understand the complexity
of how the hierarchy of dominance is established in animal societies.
With the participation of the Leibniz Zoo and Wildlife Research Institute (Leibniz-IZW) in Berlin, a team of scientists compared the intermediate dominance hierarchy
of nine populations of mammals, using a standardized set of methods and behaviors.
They found that the species ranged from strictly male-dominated to strictly female-dominated, and that the hierarchy was robust according to the method in which they were constructed
.
They also found that in female-dominated societies, animals mostly rely on signals and gestures of obedience to establish and maintain dominance, while in male-dominated societies, they mostly use aggressive behavior
.
The findings were published in
the open-access journal Frontiers in Ecology and Evolution.

Social animals often form a hierarchy of domination to avoid physical competition and injury
.
These hierarchies can be deduced from the results of intense interactions between group members
.
In many species, males and females compete for resources and interact frequently, but scientists often create separate hierarchies for each sex and use gender-specific theoretical frameworks to study social dominance
.
This is because it is often believed that dominance is driven by physical strength, while men and women often differ
in size and strength.

This traditional approach ignores the fact that dominance may be driven by traits unrelated to physical attributes such as social support, which have nothing to do with
gender.
Professor Peter Capelle, co-lead author of the Leibniz Institute for Primate Research (DPZ), a German primate research centre, said: "The binary view of female- or male-dominated societies is also too simplistic, because we now know that dominance follows a gradient that includes societies
in which men and women share power.
" Scientists use different methods to construct hierarchical relationships, further hindering the study
of dominant relationships between the sexes.
Professor Capelle said: "There is an urgent need for standardized methodological approaches and a broader theoretical framework to study the relationship
between the strengths of the sexes.
"

To achieve this, the team collected behavioral observations and used a common set of methods to establish intrasexual and intersexual dominance hierarchies
in nine mammal species (spotted hyenas, rock beavers, and seven primate species: vero lemurs, red-headed lemurs, South American baboons, crested macaques, mandrills, long-tailed monkeys, and bonobos).
They used five different indices to calculate the degree of domination of
females over males.
They then investigated whether there was a relationship between the degree of female dominance and the establishment and maintenance of dominance in a species, specifically how strongly
the animal relied on aggressive behavior (e.
g.
, pounce and bite) and obedience signals (e.
g.
, flat ears and low butt).

The team found that regardless of the method used, individuals were ranked in the hierarchy in the same order, and there was a good correlation
between all measures of female dominance.
Dr Oliver Höner, co-author from Leibniz-izw, said: "This shows that the methods used to construct hierarchies between the sexes are comparable and that the relevant measures of female dominance are reliable
.
" The scientists further confirmed that intermediate dominance varies along a continuum from strict female dominance to strict male dominance, and showed that this is independent
of the method used.

The study also revealed significant differences
in governing styles between male- and female-dominated societies.
"The higher the degree of dominance of females in a species, the less frequently the animals use aggression to establish and maintain their dominant relationships," explains
co-lead author Dr.
Elise Huchard, from the Montpellier Institute for Evolutionary Sciences (ISEM) in France.
"In female-dominated species, such as spotted hyenas, both male and female animals exhibit more submissive signals and gestures and use less aggressive behavior
than male-dominated species such as the chakma baboon.
" These results suggest that in female-dominated societies, signals are particularly important for structuring social life and may limit the use of
direct attacks in conflict.

"The fact that scientists studying different species often use different tools, methods, and behaviors to study dominance limits progress in the field," said
Dr.
Höner.
"With this work, we show that we have powerful methodological tools to study gender relations
in social species in a standardized way.
"

This study provides an important basis for future broader studies that aim to uncover the ecological and evolutionary causes
of sexual dominance variation within and across animal societies.