Activity rhythms of hamsters in a single cage compared to a simulated burrow system.
A method for measuring activity of hamsters using a stabilimeter at a 1 second sampling rate with data computer recorded as 5 minutes integrated values was developed. In a single cage without a running wheel a consistent pattern for activity was observed, consisting of (a) low levels of daytime activity until one or two hours before lights off when activity increased significantly; and (b) a peak of nocturnal activity in the first hour of the dark cycle. The inclusion of a running wheel increased and altered significantly the pattern of nocturnal activity. In further experiments animals were housed in two linked cages, one acting as light-proof burrow and the other exposed to light. Measurements were recorded from each cage independently and from two position detectors in the interconnecting tunnel. The results showed: (a) total activity, i.e., the summation of activity in both cages, was not different from activity in a single cage system; (b) low daytime activity was composed of prolonged periods of rest in the burrow plus short periods of activity in the exposed cage; the increased activity one hour before lights off was localised to the light-proof burrow; and (c) after lights off, the animals began to spend increasing periods of time in the exposed cage reaching a maximum after one hour. Replacing artificial with natural light did not change the principal features of behaviour.
Korenman
E M
EM
Department of Medical Electronics & Physics (Biophysics Section), St. Bartholomew's Hospital Medical College, London, United Kingdom.
Watson
B W
BW
Silman
R E
RE
D000818:Animals; D002940:Circadian Rhythm; D006224:Cricetinae; D006799:Housing, Animal; D008027:Light; D008297:Male; D008647:Mesocricetus; D009043:Motor Activity; D012931:Social Environment