Given our assumption that on male dominance, it is perhaps surprising, that only 58% of primate species have dominant males. Perhaps not surprising, as a result, every major primate group had at least one species which was female (or co-dominant) structures.
Indeed, with the gibbons (or lesser apes on this website, to check them out, click here to visit the home page, and then expand the species database, and click on lesser apes) all 5 species examined (there are a total of 20) have been classed as non-male dominant.
Amongst primates, this likelihood is (according to Lewis, the head of the study) relatively easily predicted, as tends to occur in the species, where there is little difference between the size of male and female members.
An example here, is clear: while a male gorilla can weigh twice that of a female, siamang gibbons only have males a couple of kg heavier than females – not surprisingly, while male gorillas are dominant, this is not the case with siamang gibbons.
It should be noted, therefore, that while 4 out the 5 species of great apes are male dominated (we assume this in humans as well, though, in the modern day, it would be hard to argue that we are not more of a co dominant species. Given that likely all the lesser apes (the gibbons) are more or less co-dominant, it follows, that even just looking at the apes, more are female dominant or co-dominant.
It would seem, also that, unlike animals like lion or zebra, females have a great deal more choice over who they mate with, and therefore, there are a range of species, where females are able to leverage this access for mating to improve their social position.
Even looking further down the evolutionary tree of primates, animals like lemurs, are largely female dominated.
It also puts an alarming angle on the female dominant or co dominant ape species – the bonobo is considered endangered, with an estimated wild population which is thought to lie within the range of 10,000-50,000 and is officially classed as endangered, while of the 20 gibbon species, 19 are considered endangered.
Our own behaviour may well change this rather more rapidly than we should over the next 50 years. Should there be less land, and therefore less food, even a small difference in weight may well give an individual an advantage over another. In this instance, even the small dimorphism between males and females, might mean that males start taking a more dominant role.
Unfortunately, without the ability to heavily slam the brakes on, on our continued destruction of the rainforests around the world, it is hard for us to do anything about this at the current time.
The study did go on to note, that the earliest species that were studied, included chimpanzees, baboons and macaques, which all live in male dominated groups, so we may have simply fallen into the assumption that this would hold for other primates as well. It should be noted, that amongst the great apes, bonobos managed to avoid detection until around 1929, so they could not have been an early species to be studied.
As an aside, will humans avoid the extinction of all non-human primates? Perhaps there is hope? Currently, 66% of the global population live in countries with either stable populations, or decreasing ones. By 2050, this is thought to be likely to increase up to 76%. Countries like India and Nigeria, alongside Indonesia, Brazil, and Mexico are all expected to still be growing in 2050, though likely a great deal slower. A UN study in 2019, predicted the world human population peaking at 10.9 billion in 2100, however a study done in 2024 has reduced this expected peak to just 10.3 billion in 2080.
I really hope that the human species can halt our expansion before we have removed the majority of the worlds rainforests – the worlds wilds are places of wonder and fascination for people of all ages from across the world. I hate to think of my great-great- grandchildren being born into a world, where the vast majority of species that are written about within this website, are things that can no longer be seen in the wild.
