Pokines uses the terrestrial mammalian microfauna from the site of El Juyo (Santander, Spain) and related sites to reconstruct the palaeoenvironment of Cantabrian Spain. A new method of reconstruction is presented, based on the relative proprtions of these microfauna, and the human ecological adaptations of the Upper Palaeolithic in Cantabrian Spain are examined as they relate to the resulting interpretation of the palaeoenvironment.