Comparative study on circadian rhythms of body temperature, heart rate, and locomotor activity in three species hamsters.

Circadian rhythms of body temperature, heart rate, and locomotor activity were observed in the unanesthetized and unrestrained Syrian hamsters, Djungarian hamsters and Chinese hamsters, and the differences in these biological characters among the three species of hamster were investigated. In each species, body temperature, heart rate, and locomotor activity in the dark period were higher than those in the light period. Heart rate of Chinese hamsters was higher than that of the others in both the light and dark periods. In addition, it was found that the body temperature of Djungarian hamsters decreased rapidly one time a day. These results show species differences in body temperature, heart rate and locomotor activity of Syrian, Djungarian and Chinese hamsters.