The movement of animals from one place to another in search of food, or to protect themselves, is known as migration.
Animals migrate because their internal clocks tell them to do so. Birds like the Siberian crane fly long distances to escape the harsh winter of their homeland, and to find food to survive.
Their internal clocks tell them that winter is approaching, and that food will be scarce. So, even before the scarcity sets in, they fly away. They stay in the new place until their internal clocks tell them that winter is over, and that they can fly home again.
Animals don’t have the internet, GPS, or even maps to find their destination. Yet each year they manage to find their way across thousands of miles of land and sea.