We 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. (thetvdb.com)