The world of primatology is star-studded with powerful and influential women, from the famed ape-focused studies of Jane Goodall and Dian Fossey to the lemur-loving Allison Jolley and Patricia Wright. Likewise, the non-human side of the primate world is notable for its instances of female dominance. While many primate groups exhibit co-dominant or male dominant social structures, lemurs stand out as one example of female dominance across almost all 108 species. Because female dominance is so unique among primates, researchers at the Duke Lemur Center and across the world are intrigued by the question of why and how female lemurs break the mold.
Social structures and power dynamics in the animal kingdom can be just as complex as those in the human world, with frequent changes of leadership. So how do behavioral researchers identify who is in charge in, say, a troop of lemurs? In some primate species, like Dian Fossey’s male-dominated mountain gorillas, males are much larger than females, making it visually apparent as to which sex has the upper hand. Lemurs, however are monomorphic, with very few physical differences between males and females.
Female lemurs may be the same size as their male counterparts, but they don’t need to throw their weight around to get priority access to food and safe sleeping spots. Simple acts of dominance like tail and fur pulling, slaps, and the occasional bite are enough to keep male lemurs in line, and it is clear by the way the males retreat from an approaching female that they know who’s in charge.
Dominance in the lemur world usually means not having to share, whether that be breakfast, a comfortable sunning spot, or even mates. Female lemurs choose who they mate with, and they will chase off any males that don’t interest them. Dominant females will also control which other females in their group get to mate at all, a phenomenon seen across primate species. All of these behavioral clues can reveal to researchers which individual is dominant at the time.
While being the dominant female may seem like you’ve got it made, it’s important to remember that with great power comes great responsibility. Lower-ranking females are likely to challenge the current dominant female at some point, and these transfers of power between females are rarely peaceful, and sometimes deadly. Dominant females may also have to deal with the added stressors of defending their territory from other groups, chasing off unwelcome outsiders, and bearing the brunt of reproduction.
So what are the benefits to being dominant at all, female or not? There are a number of theories on how dominance develops and why it is beneficial, but nearly all behavioral strategies boil down to one thing: babies. Female lemurs are the primary caretakers of their infants; after birth, they carry the babies around on their bellies and backs and nurse them for up to 6 months, which requires a great deal of energy. Without first access to the best resources, the mother may not maintain her strength well enough to keep her baby healthy, or may become so weak that her own future reproductive capabilities are compromised. Basically, if Mom’s not happy, nobody’s happy!
While some primate social strategies employ dominant males to act as protectors to their female counterparts, lemurs keep the females on the front lines, relying on their strength and aggression to keep themselves and their infants safe. There is a lot more to learn about dominance structures in primates, but in lemurs it appears that putting mom in charge gives her and her infants a better chance at survival.
From its lemurs to its leaders, the Duke Lemur Center is a great place to be a woman in science. The majority of staff and researchers at the DLC are female, and serve as role models for undergraduates, visiting students, and school children that come to visit and learn about lemurs. Female dominance is just one of the many things that make lemurs so special, and with such a wonderful team of scientists, the DLC is discovering more and more about them every day!
Lewis, Rebecca J. “Female power: a new framework for understanding “Female Dominance” in lemurs.” Folia Primatologica 91.1 (2020): 48-68.
Lewis, Rebecca J. “Female power in primates and the phenomenon of female dominance.” Annual Review of Anthropology 47 (2018): 533-551.
Huchard, Elise, and Dieter Lukas. “The effect of dominance rank on female reproductive success in social mammals.”
Nicholas M. Grebe, Alizeh Sheikh, Christine M. Drea, Integrating the female masculinization and challenge hypotheses: Female dominance, male deference, and seasonal hormone fluctuations in adult blue-eyed black lemurs (Eulemur flavifrons), Hormones and Behavior, Volume 139, 2022, 105108.