Scientists aren't really sure exactly how some animals figure out how to get to where they are going. They think that some animals use landmarks like rivers and streams to find their way. Other animals may navigate by the position of the sun and stars. Scientists think some animals use smell to figure out where they are going. And there are some species that may use the Earth's magnetic field to navigate. However they do it, migration is a behavioral adaptation that has evolved over time to help animals survive.