What images appear on the front and back of 1913-1938 nickels?

From 1913 to 1938, nickels were produced with the image of a male American Indian on the front and a bison on the back. Commonly referred to as buffalo nickels or Indian head nickels, these coins were made at the mints in Philadelphia, Denver and San Francisco.

In 1913, some of the coins portrayed the bison standing on a mound, while others showed him on a flattened line. The mound only appeared on the 1913 coins. James Earle Fraser designed the Native American image on the front of the coin. At least two men served as the model for the image: Chief Iron Tail of the Lakota Sioux and Chief Two Moons of the Cheyenne tribe. An "F" for Fraser appears on the coin under the date.