Mammalian species and genera that during the Pleistocene became dispersed in both Eurasia and North America often displayed interesting patterns and processes of evolution, illustrating phenomena such as speciation and parallel evolution between the two continents. Two lineages of Holarctic large mammals whose Pleistocene histories have several features in common are the mammoth (Mammuthus spp.) and moose (Alces spp.).

Although the ancient origins of these taxa probably lay elsewhere, both the mammoth and moose lineages underwent their early Pleistocene evolution in Eurasia. Each then dispersed, at some time during the early to middle Pleistocene, across the Bering land connection into North America. There they underwent apparently independent evolution from the Eurasian stock, producing endemic North American species. Meanwhile, evolution proceeded in Eurasia, resulting in specialized late Pleistocene forms that, in a second wave of emigration, entered North America. Understanding the Pleistocene evolution of these lineages therefore requires a Holarctic perspective, and in particular the Eurasian background is important to understanding the North American immigrants and their subsequent development.

Following Harland et al. (1990), the Pleistocene is here divided into three parts: early (ca. 1.6 my–790 ky BP), middle (ca. 790–128 ky BP), and late (ca. 128–10 ky BP).

Moose (Alces spp.)

The Eurasian record

The moose tribe (Alcini) is ultimately most closely related to the neocervine deer, currently distributed mainly in North America (Bubenik, 1990), but the origins of the present-day species [Alces alces (L.)] and its Pleistocene relatives are found in the Plio-Pleistocene of Europe. The earliest representative is Alces gallicus Azzaroli.