Circadian activity rhythms in the solitary cape molerat (Georychus capensis: bathyergidae) with some evidence of splitting.
Circadian activity patterns were measured in the solitary, subterranean Cape molerat, Georychus capensis, under fixed 12:12 LD, constant dark DD, and constant light LL photoperiods for 250 consecutive days using passive infra-red activity sensors. The molerats displayed significant nocturnal activity rhythms under 12:12 LD and free-running rhythms (23.5 h < tau > 25.8 h) under constant conditions. In one individual evidence was found of splitting of the activity rhythm under constant dark; the split rhythms free-ran with short- and long-periods of 23.6 h and 24.7 h, respectively. These data show that, despite degenerate retinae, G. capensis (i) are capable of perceiving light at the level of the circadian pacemaker; (ii) can entrain endogenous activity oscillators to fixed photoperiods; and (iii) display evidence of a free-running activity oscillator.
Lovegrove
B G
BG
Department of Zoology and Entomology, University of Natal, Scottsville, South Africa.
Papenfus
M E
ME
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D007031:Hypothalamus / Q000502:physiology; D008027:Light; D009043:Motor Activity; D012160:Retina / Q000502:physiology; D012377:Rodentia / Q000502:physiology; D012683:Sensory Deprivation / Q000502:physiology; D012934:Social Isolation; D013045:Species Specificity; D013493:Suprachiasmatic Nucleus / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology