Many animals migrate thousands of miles of land and sea, all without the use of a GPS device. How do animals take these amazing journeys without getting lost? No one really knows, though there are many theories. According to an article in The Independent that focused on pigeon migration, some believe the birds navigate the Earth using visual landmarks or their sense of smell to determine their location. More bizarre-sounding theories include the concept that pigeons use magnetism to determine if they’re north or south of home; another is that the pigeons use morphic resonance, a theory by Rupert Sheldrake, to refer to what he calls the "the basis of memory in nature ... the idea of mysterious telepathy-type interconnections between organisms and of collective memories within species."