Trend from temperate climates to mild subtropical. First lemurs; some modern groups of birds.
During this epoch, ancient species of primates and primate-like relatives first evolved. The end of the Mesozoic (the previous era) marked the conclusion of the Age of Reptiles and the start of the Age of Mammals. The explosion of mammalian life during this epoch brought about more than 22 new orders and is considered to be one of the most amazing examples of evolutionary diversification. Earth looked much different in the Paleocene. India and Africa were islands, and North America was connected to Europe, which was more like an archipelago of islands than the continental body it is today. South America and Australia were connected to Antarctica, forming one giant landmass known as Gondwana. Although temperatures fluctuated throughout the epoch, they were generally cooler than at the end of the Mesozoic and in the Eocene. It is believed that this cooling was due in part to dust and debris that was thrown into the atmosphere by the meteorite collision. Nevertheless, Earth's climate during the Paleocene was significantly warmer than it is today, and subtropical conditions existed around the world. Primate ancestors that lived during the Cretaceous were small omnivores (they ate both plant and animal material), and they were adaptable enough to survive the mass extinction and live on into the Paleocene. These ancestors gave rise to the earliest primates and some of the relatives of primates, such as tree shrews, flying lemurs, and bats, whose first representatives also occur in the fossil record at this time. Source