Throughout the Cenozoic Era -- the era we’re in now -- marsupials and their metatherian relatives flourished all over South America, filling all kinds of ecological niches and radiating into forms that still thrive on other continents. | Eons • PBS

Earth’s history includes five major mass extinctions, with up to 95% of species lost in events driven by impacts, volcanic eruptions, or potentially solar outbursts. The terminal Pleistocene extinction, though not part of the “Great Five,” saw the disappearance of North America’s megafauna, focusing on top predators and large mammals. | The Randall Carlson

At the end of the Pleistocene, Earth was ruled by formidable megafauna... dire wolves, giant cave bears, predators that shaped daily survival for early human cultures. The world was vastly different, and so were the pressures on life. Late Pleistocene extinctions struck unevenly across regions: South America lost 80% of its large mammal genera, Australia nearly all of them. When habitat collapses, the largest creatures suffer first...long gestation, high food demands, and slow maturation become

By the nineteenth century most plausible explanations for the Late Pleistocene extinctions had already been proposed. Today only two remain seriously considered: human activity or climate change. Epidemic disease is improbable, unable to cross such vast taxonomic and geographic boundaries. Classic cosmic impacts fail as well, since the extinctions were not globally synchronous. The pattern of losses still challenges simple explanations and invites a deeper look at the forces shaping Earth’s past