Our human senses are pretty incredible - but we only experience the tip of the iceberg. Imagine if you could 'see' with sound, smell food buried deep underground, or see the world in slow motion. This series explores the hidden world of animal senses. Stories covered include how elephants can hear thunderstorms hundreds of miles away, how bees distinguish between complex pheromones and the bizarre deep-sea arms race that has forced an ocean giant to evolve the largest eye on our planet - the size of a human head! Biologist Patrick Aryee and physicist Helen Czerski are on hand to explain the science behind the these amazing abilities. Shot in a spectacular and contemporary style, the series showcases some of the wildest habitats on Earth and gets up close to enchanting wildlife. This episode explores the extraordinary sense of sight in the animal world. We travel through the colours of the rainbow, across the spectrum of light our eyes can see - and beyond. Presenters Helen Czerski and Patrick Aryee reveal how caribou use UV light to avoid wolves, discover how seeing in slow motion lets dragonflies make a kill in the blink of a human eye, and show how one animal can see in pitch-darkness - without using its eyes.