Pleistocene The lower boundary of the Pleistocene Series is formally defined magnetostratigraphically as the base of the Matuyama (C2r) chronozone, isotopic stage 103. Above this point there are notable extinctions of the calcareous nanofossils: "Discoaster pentaradiatus" and "Discoaster surculus". The Pleistocene covers the recent period of repeated glaciations. The name Plio-Pleistocene has, in the past, been used to mean the last ice age. The revised definition of the Quaternary, by pushing back the start date of the Pleistocene to 2.58 Ma, results in the inclusion of all the recent repeated glaciations within the Pleistocene. The modern continents were essentially at their
Pleistocene rewilding The mountain tapir is the only extant non-tropical species of tapir. Predators of mountain tapirs include cougars, bears, and, less commonly, jaguars. Good introduction areas might include forested ecosystems of the west and east coasts, and the more scrub-like or wetland ecosystem of the south. During the Pleistocene, large populations of Proboscideans lived in North America, such as the Columbian mammoth and the American mastodon. The mastodons all became extinct at the end of the Pleistocene era, as did the mammoths of North America. However, an extant relative of the mammoth is the Asian elephant. It now resides only in