Reindeer originated in Beringia, the landmass that once connected modern-day Alaska and Siberia, roughly 1.6 million years ago. From there, they spread across the Arctic and subarctic regions of North America, Europe, and Asia as ice ages reshaped the landscape. Today, wild and domesticated reindeer live across a vast stretch of the Northern Hemisphere, and the species has a deep, intertwined history with the indigenous peoples who have depended on them for thousands of years.
An Ancient Arctic Species
The reindeer’s scientific name is Rangifer tarandus, and it is the only species in its genus. The earliest ancestors appeared in Beringia during the Pleistocene epoch, a period of dramatic climate swings that created and destroyed habitats across the northern latitudes. As glaciers advanced and retreated over hundreds of thousands of years, numerous reindeer lineages emerged and spread outward. Several of those lineages eventually went extinct, but the survivors colonized an enormous range stretching from Scandinavia to eastern Siberia and across northern North America.
Their success in some of the harshest environments on Earth comes down to a suite of specialized adaptations. Reindeer grow an extraordinarily dense winter coat that begins developing well before temperatures drop, giving them a lower critical temperature around minus 30°C (minus 22°F), meaning their bodies don’t need to burn extra energy to stay warm until it gets colder than that. Their internal clock is governed by melatonin, which regulates seasonal shifts in body weight, appetite, metabolic rate, and fur growth. Even their hooves change with the seasons: softer pads in summer for traction on wet tundra, harder edges in winter for digging through snow to reach buried lichen.
Where Reindeer Live Today
Wild reindeer populations are found across the circumpolar north. In Europe, they range through Norway, Sweden, Finland, and into Russia. Siberia holds some of the largest remaining wild herds. In North America, the same species goes by a different name: caribou. The distinction is purely geographic. Caribou are what the species is called in North America, reindeer in Eurasia. They are the same animal.
Alaska is home to several major caribou herds, including the Western Arctic herd, one of the largest in North America, and the Porcupine Caribou herd, which calves each summer on the Arctic coastal plain. Caribou also range across northern Canada, from the Yukon to Labrador, though many herds have declined significantly in recent decades.
Outside their native range, reindeer have been introduced to a handful of places by humans. In 1892, Reverend Sheldon Jackson brought reindeer from Siberia to western Alaska to provide a food source for indigenous communities. Reindeer were also introduced to the sub-Antarctic island of South Georgia, where they had a serious impact on native vegetation and invertebrate populations before eventually being removed.
Domestication and Indigenous Herding
Reindeer are one of the last large animals to be domesticated, and the timeline is still debated. In Siberia, some evidence suggests a form of reindeer management began as early as 1500 BC, though other researchers argue it started much later. In northern Scandinavia, reindeer herding most likely developed from around 800 to 900 AD during the Late Iron Age. Genetic studies point to two independent centers of domestication: one in Fennoscandia (the homeland of the Sámi people) and one in western Russia (associated with Samoyedic peoples such as the Nenets).
Before organized herding took hold, the Sámi lived alongside wild reindeer, hunting them for meat and hides while keeping a small number of tame animals as draft power for pulling sleds. By the 17th century, the Sámi had shifted to full-scale pastoral herding, and the reindeer became central to nearly every aspect of daily life. The animals provided food, clothing, and trade goods. Reindeer even functioned as a form of currency. It is difficult to overstate how thoroughly the species shaped Sámi culture, economy, and survival in the Arctic environment.
Similar patterns developed across northern Russia and into Mongolia, where various indigenous groups built entire ways of life around reindeer. The Nenets of the Yamal Peninsula in Siberia still migrate with herds numbering in the thousands, covering hundreds of kilometers each year between summer and winter pastures.
Population Cycles and Decline
Reindeer and caribou herds naturally fluctuate over long time scales. A large study tracking 43 herds across three continents found that nearly half showed evidence of population cycles, with an average cycle length of about 42 years. That means a single herd can swing from abundance to scarcity and back again over the course of a human generation, driven by a combination of predation, food availability, and weather patterns.
Layered on top of these natural cycles, human-caused changes are pushing many populations into steeper declines. Habitat loss from industrial development, climate change altering snow and vegetation patterns, and increased disturbance from roads and infrastructure have all been linked to falling numbers. Across their range, caribou and reindeer are increasingly considered threatened. Some North American caribou herds have dropped by 90% or more from their peaks, prompting emergency conservation measures in parts of Canada.
The picture is not uniformly bleak. Some herds, particularly in remote parts of Russia and Alaska, remain large and relatively stable. But the overall trend across the species’ range is downward, making reindeer conservation one of the defining Arctic wildlife challenges of this century.