Social interaction with a rhythmic rat enhances the circadian pattern of the motor activity and temperature of LL-induced arrhythmic rats

► Social interaction effects on circadian rhythms were studied. ► Under LL, rats with weak rhythms were cohoused with strong rhythmic rats. ► Power and stability of the 24h motor activity and temperature rhythm were studied. ► Living with a rhythmic rat enhances the circadian pattern of weak rhythmic rats.