Every year hundreds of millions of Monarch Butterflies arrive in the highland forests of Mexico for various points in the northern United States and fly approximately 2,500 miles.
These Monarchs are part of 3 or 4 generations, the last of which live for up to 9 months. This special breed of Monarch has genetically remarkable navigation capabilities, much of which is triggered by the environment.
It is speculated that this Monarch butterfly has a way of shutting down their reproductive system, except at precisely necessary points. This process enables the Monarch to both live longer and make the arduous trip.