Recent enrichment of megafauna in the north of Eurasia supports the concept of Pleistocene rewilding

‘Pleistocene rewilding' refers to the concept of restoring ecosystems to their state during the Pleistocene epoch, by (re‐)introducing species or their close relatives that were present during that time, in an effort to revive ecological processes that existed before human‐driven extinctions. This concept is highly controversial for both ethical and ecological reasons. Here I review evidence of recent northward range expansions of various large land mammals in boreal Eurasia, and discuss whether this provides evidence that rewilding projects might be justified and feasible. Around 100 years ago, the native boreal fauna of Eurasia included five species of large land mammals: moose Alces alces , brown bear Ursus arctos , wolf Canis lupus , reindeer Rangifer tarandus , and snow sheep Ovis nivicola , but since then the list has expanded. This is due to the introduction of bison Bison bonasus , Bison bison , muskox Ovibos moschatus , non‐native deer, and feral horses, as well as the northward expansion of wild boar Sus scrofa , roe deer Capreolus capreolus , Capreolus pygargus , and red deer Cervus canadensis . In addition, several southern species temporarily occurred in the north, including tiger Panthera tigris , sika deer Cervus nippon , and yak Bos grunniens . This ongoing enrichment of the boreal fauna is reminiscent to Pleistocene rewilding. However, so far, the abundance of expanding large mammals species remains low. Large‐scale projects on Pleistocene rewilding are labor‐intensive, expensive, and not popular enough to receive support, and therefore their realization is problematic