Sexual Selection of Beards

This entry was written by Kieran Baughan as part of a project done in BIAN 6133 ‘Human Reproductive Strategies’ at The Australian National University in 2019 Semester 2.


Modern humans and the extinct members of the genus Homo are unique and differ from other Hominins due to enhanced bipedalism and a relative loss of fur. The selective pressures resulting in this reduction of body hair has been extensively researched, yet the retention and function of strategic facial hair, such as beards, has often been neglected. Given that beards are predominantly a male trait, we can assume that this is a form of sexual dimorphism which is commonly associated with most primates. Whilst an argument could be made that the retention of facial hair in males could be a result of natural selection, most believe this trait to be the work of Darwin’s theory of sexual selection. An extensive literature review on the limited research in this area reveals three popular hypotheses. The first, describes that the retention of beards are the result of male-male competition, in which the trait is used to accentuate aggressive expressions. Second, that beards were retained due to inter-sexual selection strategies and mate choice, indicating that the trait may be attractive to females or be an honest signal of good parenting and overall health. The third and final hypothesis also assumes male-male competition, but instead the beard is used to signal high social status to other males. This paper will summarize and critique these hypotheses and shed light on which one holds the most validity as to why Homo sapiens may have retained such strategic facial hair.

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Facial Expressions and Aggression

Beards are a classical sign of masculinity and male sexual maturity, Darwin first suggested that facial hair may have evolved to communicate aggressive displays to sexually mature male competitors. Beards shape the jaw and the masculine facial structure, this allows for the expression of dominance and threating displays (Craig et al, 2019), suggesting a similar function to a gorilla’s silver back or the fascial flange of dominant male orangutans. With no significant size differences between males, Homo sapiens would need to convey dominance to competitors in other forms. The beard and even eyebrows may have served such a purpose, together it allows the individual to accentuate a variety of facial expressions including dominance and aggression. Testing such a hypothesis has proved challenging, obviously there are no Homo ancestors alive to observe and very little can be drawn from skull morphology. Several anthropologists have conducted surveys asking modern humans of both sexes to rank several images, depicting different levels of facial hair and expressions, in order of perceived aggression and dominance (Dixson & Vasey, 2012, Dixon et al, 2017, Craig et al, 2019).

The results of these studies did support the hypothesis as a bearded, angry expression was recognized quicker and males rated the bearded image as more aggressive, dominant and intimidating (Dixson & Vasey, 2012, Dixon et al, 2017, Craig et al, 2019). Whilst these results do lend some support that our ancestors may have retained facial hair as an agnostic trait, we must consider some obvious drawbacks. Firstly, modern humans, although belonging to the genus Homo, may have evolve under different selective pressures and therefore have different behaviors. Moreover, these studies don’t effectively account for cultural and societal preferences and only surveyed individuals from W.E.I.R.D (Western, Educated, Industrialized, Rich, Democratic) societies, suggesting strong biases. Unfortunately, there have been no similar surveys conducted on modern hunter-gatherer societies, which may be the most accurate modern human group to observe as this would control for horizontal cultural transfer from western societies.

Intersexual Selection and Mate Choice

Female mate choice has often been considered a driver of sexual selection leading to the evolution of highly conspicuous ornaments in males. Whilst male- male competition appears to be responsible for the majority of sexually select traits in primates, there are some examples of female mate choice. For example, the brightly coloured face of the male mandrills could indicate good health to potential mates. The same argument has been made for beards in the Homo sapiens. Some have proposed this trait may be attractive to females indicating the male is sexually mature and in good health. This hypothesis has been tested several times often by the same authors as the previous topic and in the same way, instead participance were asked to rate the images based on attractiveness rather than aggression. These tests have produced mixed results, some studies found that females preferred a clean-shaved face (Dixson & Vasey, 2012) whilst others preferred bearded men (Dixon et al, 2017) depending on location. It’s important to note that these results would be greatly influenced by culture and society, surveys on modern hunter-gatherer societies may provide more reliable results. Others have tested if beards are an honest signal of good parenting and health. Dixon & Brooks (2013) discovered that men with full beards were perceived highest for parenting, health and masculinity, perhaps suggesting the beards do indicate signals to mates. Whilst these results should be taken lightly, Roberts et al (2005), did demonstrate that men with beards appear to produce honest signals of health. Further supporting this hypothesis, females in the later stages of their menstrual cycle were more attracted to bearded men, suggesting the trait expresses greater maturity (Dixon & Brooks 2013). An interesting hypothesis proposes that hairlessness may have evolved in environments where ectoparasites are prevalent, thus indicating good health and cleanliness to potential mates (Pagel & Bodmer, 2003). If true, we would expect females to find bearded men more attractive in environments of low ectoparasites. This would provide stronger evidence of sexual selection through mate choice and may be applicable to ancestral many Homo species.

Dominance and Social Status

Living in large multi-male multi-female groups, like most of the Homo genus, creates a selection pressure for traits which express dominance and improve standing or social ranking within the group, especially in the males. Male chimpanzee for example, jostle for position amongst a social ranking, often with the most aggressive or intimidating males highest ranked. In modern hunter-gatherer societies the trend is very similar, with the most successful hunter or warrior gaining highest prestige and access to more females and resources. Facial hair has been proposed to have evolved for this purpose. As mention, beards promote sexual maturity and masculinity and accentuate aggressive behaviour and dominance, Therefore the beard appears to be the ideal trait to signal knowledge and leadership, thus, elevating an individual’s position in the society and increase access to females. Grueter, Isler & Dixson (2015) tested the presence of sexually dimorphic traits, including human beards, from several primate species and discovered such traits were most common in harems, used to gain social ranking. Importantly, the authors noted that modern hunter-gatherer societies which are predominantly comprised of kin and individual recognition of group members would be more like our ancestors and thus a better society to pose such experiments. Modern, state societies on the other hand may have strong selective pressures for agnostic traits due to larger group numbers and anonymity but are susceptible to temporal variation among cultures (Grueter, Isler & Dixson, 2015). Furthermore, A cross-cultural, social experiment proposed Muscarella & Cunningham (1996) discovered that, whilst full beards were perceived as most dominant and intimidating, baldness was perceived as the most wise and knowledgeable.


As modern humans live in large multi-male, multi-female groups, it appears likely the retention of strategic facial hair in males is a sexually selected trait, like those seen in other primates. However, whether the trait is the result of male-male competition or mate choice is yet to be resolved. Based on current literature, woman don’t appear to be more attract to bearded men, suggesting the trait is not selected for through mate choice. Although the hypothesis that a beardless face is more attractive in locations of high ectoparasites, deserves more attention. It’s more likely that beards are the result of male-male competition acting as an agnostic trait. Experimentation strongly supports this hypothesis, as bearded men are often perceived as more dominant and aggressive, especially to other males. This type of display is likely to aid the individual when trying to rise in social ranking which ultimately leads to more mating opportunities. Research into the perception of beards in modern hunter-gatherer societies are desperately needed, as studies on W.E.I.R.D societies are highly variable. Not until this research is conducted, are we likely to get more relevant information on why Homo sapiens and possibly the Homo genus retained strategic facial hair.


Grueter, C. C., Isler, K., & Dixson, B. J. (2015). Are badges of status adaptive in large complex primate groups?. Evolution and Human Behavior, 36(5), 398-406.

Craig, B. M., Nelson, N. L., & Dixson, B. J. (2019). Sexual Selection, Agonistic Signaling, and the Effect of Beards on Recognition of Men’s Anger Displays. Psychological science, 30(5), 728-738.

Dixson, B. J., & Vasey, P. L. (2012). Beards augment perceptions of men's age, social status, and aggressiveness, but not attractiveness. Behavioral Ecology, 23(3), 481-490.

Dixson, B. J., & Brooks, R. C. (2013). The role of facial hair in women's perceptions of men's attractiveness, health, masculinity and parenting abilities. Evolution and Human Behavior, 34(3), 236-241.

Dixson, B. J., Lee, A. J., Sherlock, J. M., & Talamas, S. N. (2017). Beneath the beard: do facial morphometrics influence the strength of judgments of men's beardedness?. Evolution and Human Behavior, 38(2), 164-174.

Muscarella, F., & Cunningham, M. R. (1996). The evolutionary significance and social perception of male pattern baldness and facial hair. Ethology and Sociobiology, 17(2), 99-117.

Pagel, M., & Bodmer, W. (2003). A naked ape would have fewer parasites. Proceedings of the Royal Society of London. Series B: Biological Sciences, 270(suppl_1), S117-S119.

Roberts, S. C., Little, A. C., Gosling, L. M., Perrett, D. I., Carter, V., Jones, B. C., … & Petrie, M. (2005). MHC-heterozygosity and human facial attractiveness. Evolution and Human Behavior, 26(3), 213-226.

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