A “mega den” of hundreds of rattlesnakes in Colorado is getting even bigger now that late summer is here and babies are being born. Thanks to livestreamed video, scientists watching the den are learning more about rattlesnakes, including how they care for their young. The rattlesnake den is home to as many as 2,000 rattlesnakes at a time. They’re being studied by researchers at California Polytechnic State University who are also enlisting the public’s help in tasks including how to tell the snakes apart. The latest attraction on Project RattleCam: dozens of baby rattlesnakes slithering among the much bigger adults.