Were non-bird dinosaurs alive in the Middle Eocene?

No. Non-bird dinosaurs went extinct 66 million years ago at the end of the Cretaceous. The Middle Eocene is 48-38 million years ago, well into the age of mammals.

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Middle Eocene

48-38 million years ago

The Middle Eocene was a warm, lush world where mammals were rapidly diversifying into new ecological roles. Early whales were fully aquatic, primitive horses were browsing in forests, and the first recognizable ancestors of many modern mammal groups were appearing.

Fun Facts

✓Basilosaurus, an early fully aquatic whale, lived during the Middle Eocene.
✓The Middle Eocene was significantly warmer than today. Tropical forests extended much farther toward the poles.
✓Many early primates, including ancestors of modern monkeys and apes, lived during the Middle Eocene.

Questions About the Middle Eocene

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