migration is one of the most inspiring events in nature. The numbers of individuals involved and the distances they travel can be enormous. For animals that live in regions with extreme seasonal change , there are two survival options:cope with the harsh climate at home or migrate to more favorable conditions elsewhere. In many cass,migration also gives newborns a better chance of survival. while manyfish,birds, and mammals make long migrations,the monarch butterfly's journey of up to 2,200 miles (3,500km) is all the more heroic because of the insectnd 's size and fragility. It is also a great mystery. The butterflies that return south in fall are often the great-great-grandchildren of the butterflies that left in the spring,and yet somehow they are able to find their way back to the very same grove of trees.