Body size and sexual dimorphism among a population of corsac and red foxes in central Mongolia

, Linnaeus, 1758), which are among the widestranging carnivores in northern and central Asia (Macdon-ald and Sillero-Zubiri 2004). Accounts of the corsac fox,based mainly on hunting records and anecdotal reports,suggest that males tend to be larger than females (Hept-ner and Naumov 1992, Poyarkov and Ovsyanikov 2004).Studies of the red fox, the widest ranging member of theCarnivora, also indicate that males tend to be heavierand larger than females in many populations (Ables1975,Davis 1977, Cavallini 1995, Macdonald and Reynolds2004), although in some areas, little dimorphism exists(Macdonald et al. 1999). In Mongolia, both the corsacand red fox occupy a broad zone of sympatry whichextends across the grassland steppe, semi-desert, anddesert ecozones of the country (Mallon 1985). Despitetheir expansive ranges, few published details of thephysical characteristics of either species exist in Mon-golia and other parts of northern and central Asia. Dataon red foxes from other regions are available for com-parison, but little morphological data on corsacs havebeen recorded, most of which are approximate.In 2004, we began a study of corsac and red foxbehavior and ecology in the Ikh Nart Nature Reserve ofcentral Mongolia (Reading et al. 2007). Our studyinvolved capturing, radio-collaring, and releasing individ-uals of both species to obtain information on rangingbehavior. During captures, we weighed and measuredfoxes prior to release. In this Short Note, we report theseweights and measurements and examine whether sexualdimorphism exists within each species to complementexisting knowledge on fox morphology.Ikh Nart Nature Reserve (hereafter Ikh Nart) is a rela-tively small protected area (666 km