Chaetophractus villosus (Dasypodidae), a medium-sized armadillo with burrowing habits, is one of the natural agents whose activities play a major role in archaeological deposit disturbance in the Pampean Region in Argentina. This paper presents the results of a comparative analysis between the archaeological materials collected from 32 currently active burrows and the remains collected in the sedimentary matrix identified as burrow filling during excavations of El Guanaco Site 1, Sector 1. As a general tendency, it was possible to establish that C. villosus removes both lithic and faunal materials that are 3 cm long or less. As an exception, materials up to 7 cm long are displaced. The distribution observed during the excavation of currently active burrows indicates that materials concentrate around the burrows' entrances. Copyright © 2011 John Wiley & Sons, Ltd.