Biologists from the National Park Service found a quartet of mountain lion kittens in Southern California. They visited the mountain lion den while the mother cat, known as P-62, was away. The researchers took tissue samples, tagged the kittens' ears, and did a general health check. The newly minted mountain lions are about a month old and weigh four to five pounds each. Biologists are tracking this crew to understand how the big cats survive in an increasingly urbanized environment.