Rhythms of locomotor activity and burrow use under seminatural conditions in Ctenomys talarum (Rodentia, Octodontidae)

Ctenomys are subterranean rodents that perform most of their daily activiti es in dark, thermally stable burrow systems. In this paper the dependence o f Ctenomys talarum (Thomas, 1898) activity rhythms on either photoperiod an d ambient temperature was analyzed, as well as permanency and preference fo r different sectors of a burrow system. 25 % of the individuals showed rhyt hmicity in their activities. Thus, luminous stimuli and ambient temperature did not affect activity pattern in this species. Furthermore, individuals of C. talarum did not show any generalized pattern of preference and perman ency on defined sectors of the artificial burrow system.