It's nighttime; shh, all the animals are sleeping.
I once came across a "ghost" webcam. This webcam was set up in an old library where ghosts were purported to have been seen. Visitors were encouraged to watch closely and post anything unusual. There were lots of crazy things posted, but I never saw anything. And I watched for minutes!
While I was writing this, there was some kind of activity on the Africa-cam. I heard some splashing around. The webcam must be motion activated because the scene moved to try to get a close up of the activity.
Unfortunately, with all the constant re-buffering going on, I didn't get to see any big cuddly lions getting a late-night drink.