Human pressures have led to hundreds of species extinctions and have narrowed the distribution of many of the remaining species. These changes influence our understanding of global macroecological patterns, but this influence has been rarely explored. Two of these patterns, the Rapoport’s rule on range size distributions and the Bergmann’s rule on body mass distributions, have been largely investigated in macroecology, often under the assumption that observable patterns reflect natural processes. We assessed the extent to which humans have re-shaped the observable patterns of range size and body mass distribution in terrestrial mammals globally. We analysed the role of extrinsic (biogeography, environmental, climate, human pressure) and intrinsic (biology) variables in predicting range size of individual species, and the role of human and environmental variables in predicting body mass patterns in species assemblages. We found a dominant role of human and climatic variables over biological variables in predicting the distribution of range size in terrestrial mammals. We also found that both median and maximum body size in mammalian assemblages would be much higher if human impacts were minimal, especially in areas that are highly accessible to humans and where natural land cover has been converted. Our results provide evidence of the pervasive effects of anthropogenic impact on nature, and shows human-induced distortion of global macroecological patterns. While in the short term human pressures are causing species decline and extinction, in the long term they are causing a broad re-shaping of animal communities with yet unpredicted ecological implications.