The Pliocene was an epoch in Earth's history, which was home to predators such as Terror Birds and Thylacosmilus. This epoch marked the dawn of man, as the Australopithecus, primitive hominids, evolved during this time.
Visits and incursions
An Anomaly to the future opened in the Pliocene and a Future Bird came through and took control of a pack of Thylacosmilus. The Thylacosmilus and the Future Bird subsequently went through another Anomaly to present day Peru. Two of the Thylacosmilus were killed, the other four were returned through the Anomaly, and the Future Bird fled back into the Pliocene through the Anomaly before it closed.
In order to prevent humanity ruining the Earth by creating the Future Predators, Helen Cutter started a mission to travel through the Anomalies to the Pliocene and wipe out the first Australopithecus to stop humanity's evolution.
Helen opened an Anomaly from the Cretaceous to the Great Rift Valley in the time in the Pliocene 4 million years ago when Australopithecus evolved, and went through. Danny Quinn followed Helen through the Anomaly into the Pliocene to try and stop her, and Danny was in turn followed through the Anomaly by a Raptor.
Helen reached Site 333 and managed to kill twelve Australopithecus there by poisoning their water, and Danny arrived in the aftermath. Before Helen could move on and kill any more Australopithecus, she and the Raptor which had followed Danny into the Pliocene were both killed when the Raptor pushed itself and Helen off of a cliff. Danny then returned across the Valley to the Cretaceous Anomaly, but it closed just before he could go back through; marooning him in the Pliocene.
After Danny Quinn was marooned in the Pliocene, he spent six months fighting against Terror Birds there. He also at some point apparently returned to Helen Cutter's corpse at Site 333 and found her documents of Philip Burton.
An Anomaly to the Pliocene opened up in a prison in 2011 on the exact same spot as another Anomaly, and a Terror Bird and Danny Quinn came through. When Patrick Quinn escaped into the Pliocene Anomaly, Danny followed him back through into the Pliocene to stop Patrick from reaching another human time period.
The New West Warehouse district - Cenozoic forest Anomaly may have linked to the Pliocene, as three Titanis walleri Terror Birds came through.
The Pliocene was an epoch lasting from 5.33 to 2.58 million years ago, which saw the evolution of elephants and Australopithecus. Climates became cooler, drier and more seasonal in the Pliocene, similar to modern climates; the average global temperature was only 2-3 degrees Celsius higher than today's, and global sea levels were twenty-five metres higher than in the present. This change in climate over from the previous epoch caused tropical species to globally decrease and allowed grassland, conifers and deciduous forests to thrive. Both terrestrial and marine animal life in the Pliocene was essentially modern, although the former group of fauna were somewhat more primitive than today.