Arctic ground squirrels are the northernmost hibernating mammal and they live in an extremely harsh and unpredictable environment with a short growing season. This environment has the potential to exert strong selection pressure on life-history traits and behaviour. I studied arctic ground squirrels living at high elevation in alpine tundra in Southwest Yukon in order to answer 5 main questions: (1) How do changes in elevation and associated habitat affect demography of arctic ground squirrels? (2) What is the fate of adult males that disappear at very high rates from local populations? (3) What factors are correlated with an individual's probability of death and dispersal? (4) What factors are correlated with a male's reproductive [...]