Eocene, these are still biologists.
Almost 34 million years ago, the late Eocene epoch gave way to the Oligocene.
Fossil records suggest that Lagomorpha
evolved in Asia at least 40 million years ago, during the Eocene period.
Fossil kingfishers have been described from Lower Eocene rocks in Wyoming and Middle Eocene rocks in Germany,
around 30-40 million years ago.
The oldest squirrel fossil, Hesperopetes,
dates back to the Chadronian(late Eocene, about 40-35 million years ago)
and is similar to modern flying squirrels.
During the Eocene, Earth's continents were packed more closely together and global temperatures
averaged 23.4 degrees Fahrenheit(13 degrees Celsius) warmer than they are today.
During the Eocene, the Earth's continents were packed more closely together
and global temperatures averaged 23.4 degrees Fahrenheit(13 degrees Celsius) warmer than they are today.
But size plasticity seems to have been great at this initial stage of penguin radiation: on Seymour Island, Antarctica, for example, around 10 known species of penguins ranging
in size from medium to huge apparently coexisted some 35 mya during the Priabonian Late Eocene.
But there has never been a runaway greenhouse on Earth- it would have sterilized the planet and life would
never have emerged at all- and the planet has been at least 10 degrees Celsius hotter during the Eocene 50 million years ago,
when CO2 levels were much higher.