T. rex was previously suspected to have evolved in Asia and migrated to North America, but new research shows that the direct ...

As humans migrated across North America, they may have hunted these large mammals to extinction. The overhunting hypothesis posits that these animals, unaccustomed to human predators, were easy ...

The playful North American river otter is equally at home in the water and on land. It makes its home in a burrow near the water's edge, and can thrive in river, lake, swamp, or estuary ecosystems.