Wild reindeer (Rangifer tarandus) were observed on mountain ranges in southern Norway from 1969 to 1971. Seasonal changes in herd distribution, movement, group size and activity were quantified. Traditional calving grounds were located on the Hardangorvidda plateau (60 N,7 E). Individual and social behaviour patterns were fully described including comfort grooming; eight antagonistic threat typos; courtship and displays by rutting males, including ritualised antler clashes and urine self-marking; parturition and the mother-infant bond. The mean gestation period was 227 days. Post-calving herds of up to 10,000 ranged widely. Gregariousness was related to an open habitat and social facilitation. Leadership and socially responsible roles were temporarily adopted by adult females at times of danger for the herd. Play by calves and adults occurred. Aspects of the social organisation of the population were influenced by seasonal environmental factors. The social hierarchy during winter grazing periods had the potential of reducing the physical condition of low-ranking animals; the presence and size of hard antlers was the main determinant of social rank. Winter winds over 30 km/h prevented grazing and provoked heat conservation and heat generation behaviour strategies. The effect of insect harassment on reindeer activity and social structure in summer was quantified and a close relationship with air temperature and wind speed established. Similar results were obtained for Alaskan barren-ground caribou on Arctic tundra in summer 1972. A provisional energy budget is constructed from observed activity times and estimated energy costs. Maximum energy was conserved at calving time (1.3 x BMR), and maximum energy expended in summer (2.5 x BMR) and in the autumn hunt (3.8 x BMR). Comparisons between populations on different mountain ranges revealed no basic behavioural differences. Mountain/tundra Rangifer form multi-male rutting groups while woodland Rangifer form single-male harems. Reindeer do not perform the caribou's particular alarm stance, excitation jump, head-high threat or headbobbing, but do exhibit multiple sucklings of one female by several calves. However the mass of behavioural evidence supports their taxonomic classification as one species.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:662893 |
| Date | January 1978 |
| Creators | Thomson, Brian R. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/13120 |
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