middle Eocene Epoch

The Middle Eocene Epoch, a division of the Eocene Epoch, spans from approximately 47.8 to 38 million years ago. The Eocene Epoch itself is the second of three divisions of the Paleogene Period, which lasted from 66 to 23 million years ago. The name "Eocene" comes from the Greek word for "dawn," reflecting the significant diversification of many modern life forms, particularly mammals and mollusks, during this time.1

During the Eocene, global climates were warm and humid, supporting widespread temperate and subtropical forests. Fossil evidence from North America indicates that Eocene forests contained trees and plants similar to those found in Central and South America today. This epoch also saw the emergence of key mammal groups, including odd-toed ungulates (like early horses, rhinoceroses, and tapirs) and even-toed ungulates (such as deer and cattle). Furthermore, the Eocene marks the first appearance of marine mammals like cetaceans (whales, dolphins) and sirenians (manatees, dugongs), as well as early elephants and bats.1