Reindeer is key for the maintenance of the tundra ecosystem. We need to increase investments for the management and conservation of this majestic species, as this will benefit not only nature but also many communities that rely on reindeer for their economy, identity, and emotional well-being. 4/🦌

We predict declines in population size over 80% by 2100, under a business-as-usual climate change scenario, with North American populations being the most vulnerable. 3/🦌

We show that reindeer was able to survive abrupt climatic fluctuations of the past thanks to its ability to travel long distances to track suitable environments and to survive in low population numbers. Still, these traits might not be enough to protect it from future climatic warming. 2/🦌

We used historical and modern observations, fossils, ancient DNA and ecological models to simulate the abundance and distribution of wild reindeer and caribou since the Last Glacial Maximum until present, and we directly compared these to future predictions. 1/🦌