The Myth of the Alpha Male: Rare Among Primates

Photo credit: Zac Mills, the Wildlife Collective

Researchers have studied physical encounters in 121 primate species and found that half of all aggressive interactions were between males and females. Males won these contests in 17% of primate populations, with females dominating in 13%. This makes it almost as likely for females to dominate males.

For the remaining 70% of primate populations, there was no clear-cut dominance of one sex over the other. Why does this result differ from previous research? This study assessed individual contests rather than categorising species based on physical attributes or social structure. But it did find some common threads…

Male dominance is common when males are much larger than females, have multiple mates, are terrestrial, or have weapons (like large canine teeth). Female dominance is common among similar-sized sexes, a scarcity of females, one sexual partner, and arboreal species. This makes it easier to flee an attacker.

As for the 70% where there was no sex bias: these species tend to be smaller (like marmosets, tamarins, and capuchins), have a prehensile tail to grasp things, mating systems which are neither polygynous or monogamous, and minimal size difference. In other words: somewhere in the middle!

So, what does this mean for orangutans? Despite having a social structure that includes a dominant male, they aren’t strictly “male-dominated”. Their social structure is more complex. Orangutans are generally solitary; their main social bonds and interactions are between mother and baby.

Some males develop cheek flanges and throat sacs to help establish territories and attract females. But not all males develop these features; some are unflanged and still mate and father offspring. Dominance is influenced by environmental factors like food availability, demonstrating how agile orangutans can be.

These findings suggest that social hierarchies in primates aren’t hardwired. Instead, they are shaped by the environment, mating system, and group composition.

Reference: Huchard et al (2025) “The evolution of male–female dominance relations in primate societies.” PNAS Vol. 122, No. 28