Dasypus hybridus (Desmarest, 1804) inhabits open fields in southern South America. Burrows of D. hybridus were cylindrical with a conical end. They had an entrance and a single tunnel without branches. Three locations of the burrows in the terrain were detected: in banks of dried waterways, near rocks, and in open field. The orientation of 29 burrow mouths was not random and, although they did not point to any cardinal point, in particular there was a strong tendency to avoid the south quadrant. In a sample area of 90 x 140 m, burrow mouths were arranged in a random spatial pattern with a density of 25.4 burrows per ha. Great variation in burrow length was found (118.8 ± 105.69 cm, CV = 89.0%). Tunnels may be used as refuges and/or for thermoregulation. The orientation of burrow mouths can also be related to thermoregulation as tunnels are covered from dominant winds, and, for many hours every day, the temperature at the mouths can be influenced by insolation. The possible existence of shelter-burrows and resting-burrows is discussed.

The field work was supported by VIDA SILVESTRE, Sociedad Uruguaya para la Conservación de la Naturaleza.