[A comparison of the behavioral response of the field mouse (Apodemus sylvaticus L.) to a 24 hour fast as measured by...

1. The "general activity" of Apodemus Sylvaticus L. has been recorded and analysed using two techniques: a) in an actograph, several components of the "general activity" have been recorded and quantified over 24 hours, including wheel running, locomotion in various areas of the enclosure, nest occupancy, drinking, eating and hoarding; b) in a breeding cage, ten times smaller than the actograph and where the possibilities of locomotion are considerably reduced, the wheel running only has been recorded. In these two situations, we have compared the effects of a food deprivation for 24 hours. 2. In the actograph, starvation increases the general locomotion in the enclosure without detectable changes in wheel running. On the other hand, in the breeding cage, wheel running is somewhat increased. 3. Refeeding results in decreased wheel running under both experimental conditions, and restores general locomotion in the actograph to the predeprivation level. 4. These results are discussed in view of the current literature. The apparent disagreement between our results and those of other workers is attributed to the fact that the latter used experimental conditions where the measured response was predetermined by the lack of choice in expressed responses which were offered to the animal. Consequently, we suggest that the interpretation of such experiments can be improved by allowing a choice of possible behavioural response and that each of them should be recorded separately.