12th Annual Smithsonian Magazine Photo Contest Natural World
Testing the Air

A young bison bull in Custer State Park exhibiting flehmen, a behavior that allows him to determine if cows are ready to mate.

Photo Detail
Date Taken: 09.2012
Date Uploaded: 11.2014
Photo Location: South Dakota, United States of America
Camera: Canon EOS 7D
Copyright: © Cathy Illg