For the more information about the geologic resources of the National Park Service, please visit http://www.nature.nps.gov/geology/.


Why migrate?

Bison herd crossing stream.
Bison migration.

The annual synchronized movements of millions of individuals participating in a journey that has repeated itself for thousands of generations, captivates the imagination. Migration is a strategy to survive, allowing wildlife to:

  • Track seasonal food resources
  • Escape dry seasons
  • Avoid harsh winters
  • Evade heavy predation during reproductive periods

Last Updated: December 15, 2010