Reindeer/Caribou

In North America and Greenland, the species Rangifer tarandus is known as “caribou”. This same species is called “reindeer” in Eurasia. In many Arctic nations, large herds are managed as free-ranging livestock. In Scandinavia, these semi-domesticated reindeer/caribou can even outnumber wild populations!

Wild reindeer/caribou herds can sometimes get so large that they overgraze the lichen they depend on. As they deplete their food source, the population crashes. As the forage quality recovers, so does the population. We know about these large fluctuations in part because Indigenous Peoples have long documented these ups and downs.

Although reindeer/caribou herds are expected to go up and down, the sustained reduction in many populations since the 1990s is unprecedented. For migratory herds (making the longest terrestrial migrations on earth!) this is likely due to climate change, as plants adapt to warmer temperatures and more rain-on-snow events occur. Infrastructure and development can also hinder movements between winter range, calving grounds, and summer range.

These migrations are important not only for a functioning ecosystem (as reindeer transfer nutrients and support food webs) but are woven into the culture of Arctic Peoples. Reindeer/caribou provide food security in a harsh climate and contribute to local economies.

There are several variants, or sub-species, of reindeer/caribou that show unique behaviors and have a different appearance based on their local landscape. These variants are also called “ecotypes” since they can be defined by the ecosystem as well as genetics. There are four main ecotypes – migratory tundra, Arctic islands, mountain, and forest.