Nellie is a well-trained sea otter at Point Defiance Zoo & Aquarium in Tacoma, Wash. If you've ever been to summer camp, or to a college freshman's dorm room, you've probably seen cup stacking like this. The difference? The otter is probably better at it than your friend Lisa. Sea otters are an endangered species. Where there were once hundreds of thousands, only a few thousand remain today. They're awfully cute; don't you think we should keep them around? via i09

Want to recommend a video? Tweet it to @Discovery_News with the hashtag #GottaSeeVideos.