For the second summer, hundreds of rattlesnakes in a Colorado "mega den" are being livestreamed as part of Project RattleCam.

Rattlecam, a camera used by researchers and available to the public, is live streaming again. The camera is near a mega den that is home to as many as 2,000 snakes.

From now on, dogs and cats that are subjects to scientific research in Colorado will be valued for their service and given ...