Solitary felids are commonly associated with structurally complex habitats, where their foraging success is attributed to stealth and remaining undetected by competitive scavengers. Research in North America suggests that pumas (Puma concolor), a wide-ranging species found throughout the Americas, conform to the general characteristics of solitary felids and avoid open grasslands with aggregating prey. Researchers hypothesize that pumas are limited to structurally complex habitats in North America because of pressures from other large, terrestrial competitors. We explored the spatial ecology of pumas in open habitat with aggregating prey in Chilean Patagonia, where pumas lack large, terrestrial competitors. We tracked 11 pumas over 30 months (intensive location data for 9 pumas with GPS collars for 9.33 ± 5.66 months each) in an area where mixed steppe grasslands composed 53% of the study area and carried 98% of available prey biomass, to track resource use relative to availability, assess daily movements, quantify home ranges and calculate their density. As determined by location data and kill sites, Patagonia pumas were primarily associated with open habitats with high prey biomass, but at finer scales, preferentially selected for habitat with complex structure. On average, pumas traveled 13.42 ± 2.50 km per day. Estimated 95% fixed kernel home ranges averaged 98 ± 31.8 km2 for females and 211 ± 138.8 km2 for males, with high spatial overlap within and between the sexes. In a multivariate analysis, available prey biomass was the strongest predictor of variation in the size of an individual puma's home range. Finally, we determined a total puma density of 3.44 pumas/100 km2, a significantly smaller estimate than previously reported for Patagonia, but similar to densities reported for North America.