Prehistoric animals. Artwork of animals that lived in the Oligocene (34 to 23 million years ago) and Miocene (23 to 5.33 million years ago) epochs. Below and on the tree are various extinct species of monkey and ape, including Proconsul (bottom). At lower left is a phorusrhacos (Phorusrhacos longissimus), a species of flightless bird from the Miocene. Also depicted is Amebelodon, (grey,centre) a Miocene proboscidean distantly related to the modern elephant. Moropus is depicted standing in the stream (centre left). The climate became increasingly arid during the Miocene and grazing animals adapted to live in savannah environments were successful.