The climate was very cold, during one of the most important Ice Ages or Glaciations that affected the whole planet. During
 the Oligocene, around the world began a cooling that drastically 
changed the life of mammals, the world was impacted by one of Earth's 
most dramatic climate changes during The Age of Mammals. A
 rapid onset of Antarctic glaciation resulted in planetary cooling, 
which began about 34 million years ago, at the end of the Eocene and 
early Oligocene.