Quick Take Sudan, the last male northern white rhino, died, underscoring extinction and the emotional toll on caretakers.

These slow-moving, eucalyptus-eating marsupials native to Australia are beloved for their sweet demeanors and distinctly non-human adorableness. However, koalas do share one feature in common with ...

Everyone knows that dinosaurs are extinct, and most people have some idea about how it might have occurred. But the exact periods in history when it happened are less well known. Was it a single ...

Where they lived: Dinosaur fossils have been found on every continent, including Antarctica. What they ate: Some ate plants, while others ate animals, including other dinosaurs. How big they were: The ...