In collaboration with international research partners, we have attached dosimeters with GPS to free-ranging wildlife (Reindeer in Norway, Brown Bear in Sweden, and Wild Boar and Snakes in Japan). The instruments collect dosimetry as well as location data of the animals in almost real-time frequencies, as the animals move naturally through habitats that vary widely in contaminant levels. We have thus obtained much more accurate measurements than have been possible before (external dose was derived from soil samples and a Concentration Ratio, with large uncertainties). This research has shown us how animals use spatially complex micro-habitats over time, and how this results in dose variations. The added precision is most important in dose-effect research, which has traditionally been plagued by large uncertainties. Our research is providing much needed data on the effects of chronic exposures to low-dose rate exposures and some results of mammalian models, such as boar, can be extrapolated to humans.