Visits and incursions
An Anomaly to the Pleistocene apparently opened up in the 1990s - early 2000s, and a Smilodon cub came through before the Anomaly closed. It was ultimately killed years later as an adult when it was locked in the Creature Prison with Oliver Leek's other captive creatures.
An Anomaly to the Pleistocene opened on the present day M25 and a Columbian Mammoth came through. The Mammoth was marooned in the present when the Anomaly closed, and thus it was held in captivity by the Anomaly Research Centre until it could be returned to its own time.
The New West Warehouse district - Cenozoic forest Anomaly may have linked to the Early Pleistocene, as three Titanis walleri came through.
The Pleistocene lasted from 2,588,000 to 11,700 years ago. There was a series of major glacial periods during this time, with the end of the Pleistocene marking the end of the last glacial period well-known as the Ice Age. The Pleistocene's climate has been hypothesised to have been a constant El Niño, and the modern continents were more or less in their current positions in the Pleistocene. Fauna in the Pleistocene was essentially modern, although many animals were much larger than they are today, and they suffered severe stress and were forced to mass-migrate south during the glacial periods.