Four adorable western Santa Cruz Galápagos tortoise babies are now on display at Philadelphia Zoo after their 100-year-old 'Mommy' reproduced for the first time.

Researchers may have discovered Mississippi's largest ever mosasaur after pulling a Cretaceous-aged fossil out of a riverbed ...

Imagine spending your day suspended upside down in a leafy canopy, moving so slowly that even the wind seems fast. For sloths ...

Imagine a world where forests echoed with the slow, thunderous steps of creatures as large as small cars. Millions of years ...