from 65 million years ago to the present

Introduction: By the end of the Mesozoic Era, the dinosaurs were gone forever. The continents started crashing into each other again. India was south of the equator off the east African coast by the end of the Cretaceous Period, and at the beginning of the Tertiary, India began charging toward Asia very fast geologically speaking. Its eventual crash into Asia caused the rise of the Himalayan mountains. Due to the movement of continents, the Alps and Rockies also arose during this time. It was during the Cenozoic that a great Ice Age began, and in fact, that Ice Age is not yet over. The oceans cooled substantially and many species disappeared. At the peak of the Ice Age, at least 32% of the Earth was covered by huge glaciers, thousands of feet thick. It seems that our civilization developed during a lull in the middle of this Ice Age. Even today 5 million square miles of our planet remain covered in glaciers. Whether the Ice Age will continue or end no one knows.

Life: The Age of Mammals began in the Cenozoic Era. Although small mammals arose earlier during the Age of Dinosaurs, they stayed small and hidden. During Cenozoic time, which began when the dinosaurs disappeared at the end of the Cretaceous Period, mammals finally had their day. They diversified quickly and spread all over the globe. Also, the first grasses appeared early in the Tertiary Period, creating great grasslands for emerging mammals to inhabit. Life in the oceans did not go through the kind of magnificent changes occurring on land. The one exception is the appearance of ocean-going mammals: the whales and dolphins.

On land, large mammals and great flightless birds appeared (for example, the "horse-eating bird!"). Ungulates of all kinds roamed the land, including an ancient rhinoceros, Indrichotherium, the greatest land mammal that ever lived. It stood 18 feet high at the shoulder—which is the height of a modern giraffe from ground to the top of its head! This was also the time of the giant mammoths, a larger distant relative of today's elephants.

Primates evolved during the Tertiary Period and had greatly diversified by the Quaternary. From these primates modern humans eventually evolved.