Overview: How do animals make sense of the world? This journey starts inside a swan's egg, joins a wildebeest on migration and flies with a house martin from Africa to England. Discover why a moth flies to a light, and how a pigeon becomes confused by magnetic forces. Why do sharks bite communication cables, hatching turtles visit a hotel, spiders lure moths with sexual chemicals and fireflies flash deadly signals? And why do monarch butterflies, guided by a mysterious sense, congregate in a breathtaking spectacle?