Many animals migrate (i.e., move from one region to another and back in search of resources, often seasonally) during the course of their lives. Migratory behavior can be learned or innate, depending on the species. Monarch butterflies present an interesting case: their migration is inter-generational. One generation travels to their overwintering grounds in California and Mexico, where they lay eggs. The generation that hatches from these eggs is the one that proceeds back to the species’ summer feeding grounds.