Female dominance in blue-eyed black lemurs (Eulemur macaco flavifrons)

Female dominance is unusual among mammals and has been described in detail for only a handful of species. Here we present data on the frequency and outcome of dominance interactions in seven semi-free ranging and captive groups of blue-eyed black lemurs (Eulemur macaco flavifrons) housed at the Duke University Primate Center. We collected over 260 hours of focal data during which all occurrences of dominant-subordinate interactions were recorded. We collected data outside the typical breeding and birthing seasons for this species, thus eliminating possible confounding factors and increased aggression associated with these periods. We found that females were dominant over males in all seven groups, with females winning 99% of all dominance interactions. E. in. flavifrons used aggressive dominance (e.g. chase, cuff, bite) in 81% of all interactions, with the remainder of interactions being decided using social dominance (e.g. deference in the form of supplants or cowers). Older females were dominant over younger females in two out of three multi-female groups (in each case, younger females were daughters), and younger males (sons of the dominant female) received less aggression from females than did older males (n = 2 groups). Caging and group size appear to play a minimal role in the expression of female dominance. While confirmation must await further observations on free-ranging groups of E. in. flavifrons, our data strongly suggest that this subspecies can be characterized as female dominant.