Game reserves (GR) in Tanzania have been found to support similar or lower densities of large mammals compared with National parks (NP). But as these areas usually differ considerably not only in regard to management but also to environmental factors, we assessed the relative importance of vegetation cover, species-specific habitat preferences and legal (trophy hunting) and illegal off-take for observed differences in species-specific densities. In the Katavi ecosystem, open habitats were characteristic elements of Katavi NP, while Rukwa GR was