Activity patterns in a subterranean social rodent, Spalacopus cyanus (Octodontidae)

Daily patterns of activity were studied under laboratory conditions in 12 coruros, Spalacopus cyanus, subterranean social rodents originally from Chile. When able to burrow, coruros spent 90% of the total time underground, and surface activity occurred during the 1st hours of darkness. When prevented from burrowing, locomotory activity of coruro groups peaked near the onset of darkness but also occurred during episodes of light. Individually housed coruros displayed a clear nocturnal activity pattern. Coruros exhibited endogenous circadian rhythms entrained by a light-dark cycle.