The Miocene, 5my to 23my, occured during the Cenozoic era. At the begining of the era Earth was hot but by the end, 1.5 my, it was cold. During this period, mammals multiplied rapidly.

This drawing shows the position of the continents during the Miocene. The Miocene was part of the Cenozoic era, a time when mammals multipled rapidly.

Earth looked like this when mammals began to multiply.

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