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.