Reacción a "Study questions the social dominance of males in most primate societies"

I find the article extremely interesting and it belongs to a current of studies that analyze sexual differences from a perspective in accordance with that of our society today. It is very interesting that in most primate populations there is no clear dominance of one sex or the other, but when this occurs it is because one sex dominates over the other in the control of reproduction. This is the hypothesis that is most strongly supported by the data and this control of reproduction is achieved in various ways (from being able to flee from unwanted suitors, to living in a monogamous rather than a polygamous society).

It is important to clarify that the authors consider dominance when a minimum of 90% of conflicts are won by a particular sex; all species (or populations) that fall below this are considered “moderately” dominant (although in 89% of cases one or the other wins). Based on this, they find that in 38% of the species males dominate females and in 21% females dominate males. But in most cases (41 %) there is no clear dominance of one sex over the other.

Something particularly interesting, and perhaps thought-provoking for humans, is that this can vary between populations within the same species. There are populations in which dominance varies according to environmental conditions and, while in one population males or females clearly dominate over the opposite sex, this may not be so clear in others. That is why the researchers give data on populations and not just species, and there the numbers are even closer between the sexes, with 17% of primate populations studied being male-dominated and 13% of populations being female-dominated. Again, the vast majority are in an intermediate territory, with 70 % of populations classified as “moderate”.

Something particularly interesting, and perhaps thought-provoking for humans, is that this can vary between populations within the same species. There are populations in which dominance varies according to environmental conditions and, while in one population males or females clearly dominate over the opposite sex, this may not be so clear in others. That is why the researchers give data on populations and not just species, and there the numbers are even closer between the sexes, with 17% of primate populations studied being male-dominated and 13% of populations being female-dominated. Again, the vast majority are in an intermediate territory, with 70 % of populations classified as “moderate”.

In future studies it will be interesting to study these populations that have fallen into the “moderate” category. One might suspect that the authors have classified as “moderate” many species or populations in which males dominate females in about 80 % of the conflicts, but this does not seem to be the case. In the absence of studying the data provided by the authors of the study in the supplementary material, it can be intuited that these intermediate populations are very varied. In the first figure of the paper you can see the proportions of these species (and populations) below 90% dominance, and they are certainly very heterogeneous: in some the females are more successful and in others, the males, without a clear appreciable tendency.

On a personal level I have found it very interesting how abandoning arboreal life has favored male dominance. The inability of females to flee between branches, the possibility of significant size differences between males and females, the development of “weapons” (such as tusks) and other traits as a result of living at ground level have given some advantage to males over females. The authors speculate briefly about the possibility that this may have occurred with pinnipeds and that there is a difference between those species that breed in water and those that breed on land.

I also found it very interesting how this study highlights bonobos as a rarity. For a long time it has been assumed that the origin of female dominance in bonobos was due to the coalitions they are able to form to confront males, but, after studying the 121 species analyzed in this study, it seems that female coalitions are neither necessary nor sufficient to explain female dominance. It seems that bonobos are an exception, a rarity among primates, and not because females dominate males (because this happens in many other species, as shown here) but because of the way they have achieved it.