COLORADO, USA — A "mega den" of rattlesnakes in Colorado is becoming active after the long winter. Thanks to a livestream, scientists studying the den on a craggy hillside in Colorado are ...

The moose is the largest animal in Colorado, weighing up to 1,200 pounds and standing up to 6 feet high at the shoulder. Male moose also have antlers, which can cause serious damage if you are rammed.