Seasonal development of circadian and short-term activity in captive reindeer, Rangifer tarandus L.

摘要: 1. Locomotor activity in a group of ten captive reindeer (Rangifer tarandus L.) was recorded automatically during 15-month period at the University Ume\0a, Sweden (63\dg 49\t' N). The records were complemented by observations on and rumination March, June, September December. Artificial food provided lib. 2. Reindeer have polyphasic pattern with bursts occurring both day night. The number peaks varies from 4–6 winter 6 h daylight to 6–9 summer continuous daylight. increase is brought about splitting evening peak, thereby creating an increasing gradually shorter frequencies. 3. Sunrise sunset act as \lssetpoints\rs for activity, separating it into diurnal nocturnal phase. Since predominates, essentially animal. Increasing daylength causes 1:1 fashion while ratio night length close 1:0.5. This total amount over 24 change photoperiod. 4. Food consumption 30% lower than varied accordance changes pattern 5. The time spent ruminating between meals longer summer, thus consisted relatively few periods long rumination, unlike which made up large numbers time. 6. Rumination showed rhythmical within single resting period. Reindeer found perform one several bouts each lasting approximately 50 min. 7. It concluded that regulated mainly light-dark conditions. Photoperiod presumed provide proximate factor governing seasonal variations energy intake reindeer.