American Journal of Primatology 54:181–192 (2001) © 2001 Wiley-Liss, Inc. RESEARCH ARTICLES Female Dominance in Captive Gray Mouse Lemurs (Microcebus murinus) UTE RADESPIEL* AND ELKE ZIMMERMANN Institute of Zoology, Tierärztliche Hochschule Hannover, Hannover, Germany Female dominance or female feeding priority seem to be characteristic for many lemur species, but are rare traits in other primates and mammals in general. The nocturnal lemur species, however, are underrepresented in the quantitative studies on social dominance. The aim of this study is to investigate the pattern of intersexual dominance relationships in the gray mouse lemur (Microcebus murinus), a species that is generally thought to possess a number of ancestral lemur traits. The context, distribution, and outcome of intersexual conflicts are analyzed in four captive groups of gray mouse lemurs. Intersexual conflicts occurred in the study groups in different behavioral contexts and were mostly spatial interactions (chas- ing/fleeing, approach/avoidance). The majority of conflicts were decided, and were in all but one case won by females. This is the first evidence suggesting unconditional female dominance in a cheirogaleid primate. The existence of female dominance in most families of the Lemuriformes sug- gests it is an ancient trait that evolved in their common ancestor. Am. J. Primatol. 54:181–192, 2001. © 2001 Wiley-Liss, Inc. Key words: female dominance; Microcebus murinus; lemurs; evolution INTRODUCTION Female dominance has been defined as the ability of all adult females to consis- tently evoke submissive behavior in all adult males on an individual level [Pereira et al., 1990]. In primates and mammals in general, female dominance is a very rare trait [Ralls, 1976; Hrdy, 1981; Jolly, 1984; Kappeler, 1993]. It can be distinguished from female feeding priority by its general applicability to different behavioral con- texts. The distinction between these two terms is important for the understanding of its functions and evolutionary origins. Female dominance is by definition based on a clear agonistic superiority, whereas feeding priority potentially could be based on female or male behavior in the form of “male deference” and might only serve to regulate access to essential nutritional resources [Pereira et al., 1990; Kappeler, 1993]. The available literature suggests that different lemur species have distinct forms of intersexual dominance relationships. Some species show unambiguous female dominance, some exhibit moderate female dominance (conflicts less often Contract grant sponsor: German Research Council; Contract grant number: Az Zi 345/1,5. *Correspondence to: Dr. Ute Radespiel, Institute of Zoology, Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany. E-mail: Ute.Radespiel@tiho-hannover.de Received 30 November 2000; revision accepted 2 May 2001