There are plenty of terrifying animals alive today — grizzly bears, condors, boa constrictors, great white sharks and giant hornets, to name just a handful. But there are also some very scary extinct animals that would cause modern-day humans to run away screaming.

If you're okay with chancing some bad dreams tonight, read on to learn more about several of the most frightening animals to have ever roamed the earth.

Arctodus simus: The Giant Short-Faced Bear

One of the most dangerous extinct animals was the giant short-faced bear ( Arctodus simus ). A formidable predator of North and South America, it weighed more than 1,500 pounds (680 kilograms) and stood up to 12 feet tall (3.7 meters) on its hind legs.

The giant bear's massive size and powerful jaw made it one of the most dang

See Full Page