Camping at Norris Campground in Yellowstone National Park, looked into the sky to view the stars. Partner and I each noticed four separate objects moving very, very quickly (much faster than an airplane). Partner (a skeptic) was first to point out one and said with absolute certainty, "that's a UFO". I noticed where she was pointing, spotted it, and we both followed it until it disappeared behind trees. Noticed three more after that within the space of approximately four minutes. Went into tent a few minutes later and heard a nearby pack of wolves howling.