Activity measurement by three different techniques in golden hamsters (Mesocricetus auratus): a comparison between burrow systems and standard cages

Abstract

In a previous study, golden hamsters living in self-constructed burrows showed reduced running wheel activity and decreased activity outside the burrows compared with animals without the possibility to dig burrows. Since different activity apportionments might account for that, different activity measurements were performed to show the relationship of different parts of general activity: running-wheel activity, activity inside and activity outside the bedding. Twelve hamsters in low bedding (<10 cm) were compared with 12 hamsters in deep bedding (80 cm). To further test the synchronisation to the light system, the animals were observed under light–dark (L:D) and under constant dark (D:D) conditions. Hamsters in deep bedding were significantly less synchronised to the light system, developed longer circadian rhythms tau (τ), had later activity onsets in the running wheel and a lower running wheel activity than hamsters in low bedding cages. Their activity onsets inside the bedding were later. Time differences between the onset of movements inside the bedding and the onset of running wheel activity were not significant. Thus, the later appearance of golden hamsters kept in deep bedding was not fully compensated by more activity inside the burrows.