The Madrean sky islands of North America, in southern Arizona and adjacent Sonora, harbor a great diversity of vertebrates, but data about the distribution and abundance of mammal species in this region are needed to develop strategies for their management and conservation. We used camera traps to record medium and large mammals in 4 sky islands in the state of Sonora, Mexico. We compared species richness and diversity of the 25 species detected: 1) within and outside a natural protected area; 2) according to land use (natural protected area, private property, or conservation area); 3) according to the presence or absence of cattle; and 4) among 7 monitored sites. We found no differences in richness, diversity, and composition of species in our comparative analyses, suggesting homogeneity of the communities. This homogeneity could be the result of the direct or indirect influences of past human impacts in the region, given that federal protection, type of land use, and ranching did not influence the community of medium and large mammals. We discuss the importance of maintaining sites dedicated exclusively to conservation in the region, as well as promoting management at unprotected sites to make predators compatible with livestock and agricultural production.