The Eocene, giant birds and proto-herds We cover the Eocene epoch, including early horses that lived in forests, but didn’t climb trees. We also had early forms of bores, rhinos, whales and primates. Here are a couple of articles on the Eocene. The Eocene Epoch Eocene Epoch And here’s an article about the giant flightless bird that turns out not to be a hunter after all. Eocene Big Bird Not so Scary