A mass extinction of large mammals and many birds happened about 10,000 years ago, probably caused by ice ages . Modern forms of whales. Miocene 24-5 mya More mammals, including the horses, dogs and bears. South American monkeys, apes in southern Europe, Ramapithecus. Eocene 54-38 mya Mammals abound.
Primitive whales appear .
Paleocene 65-54 mya First large mammals and primitive primates, plesiadapiforms . Primitive marsupials develop. Continents have a modern-day look. Minor extinction 82 mya. Lower 146-98 mya The heyday of the dinosaurs.