From the Arctic to the peaks of the Andes, survival at great heights takes real guts. On the Yellowstone plateau, in a rarely filmed event, see newly awakened black bears go on the hunt for newborn elk calves. Get a ringside seat at one of the toughest mating contests on the planet as male big horn sheep in the Rocky Mountains literally go head-to-head in a bloody battle for breeding rights. Fly over erupting volcanoes in Central America as fledgling parakeets test their wings above 2000-foot Nindirí Volcano in Nicaragua. At the equator, see a bat that, until recently, no one knew existed, and that boasts the largest tongue-to-body ratio of any mammal in the world. In the Chilean Andes, filmed for the first time using HD cameras, watch as three puma cubs strike out on their inaugural hunt.