The Miocene is a geological epoch that lasted from about 23 million to 5.3 million years ago. It is part of the Cenozoic Era and is known for significant changes in climate and the evolution of many plant and animal species. During this time, the Earth's climate became warmer and drier, leading to the expansion of grasslands and the decline of forests. This epoch is notable for the emergence and diversification of mammals, including early ancestors of modern horses, elephants, and whales. The Miocene also saw the rise of many primates, setting the stage for the evolution of humans in later epochs.