Much of the pioneer work in reindeer/caribou range ecology was carried out in the Soviet Union. More recently major contributions to this field of knowledge have been made by Scandinavian and North American biologists. Early work was of a descriptive nature, while a current trend has been toward analysis of the grazing process and associated plant and animal responses. Important aspects of range ecology that have received increased attention in the seven years since the First International Reindeer/Caribou Symposium include: 1) significance of the plant/animal interface (factors influencing feeding rates, plant phenology and feeding selectivity, plant production and effect of snow cover); 2) Feeding behavior and related activity patterns (comparisons between herds, the role of natural human disturbances, energetic costs and strategies of energetic efficiency); 3) Models of grazing systems (response of lichens to grazing pressures and animal/energy interactions). Comparative studies between herds, particularly in situations where specific environmental factors may differ (i.e. presence or absence of insects, predators and plant groups), have shed light on the adaptive plasticity of Rangifer tarandus Linneaus as well as its biological limitations. In light of this new knowledge it seems apparent that broad generalizations about reindeer/caribou range relationships should be approached with caution. Single factor, cause and effect relationships tend to be the exception rather than the rule. Recent interest in the role of secondary chemicals in plant as defenses against herbivores should focus new research on this topic of importance to the understanding of reindeer/caribou range relations.