At the time of the Buffalo Nickel’s inception, the previous lower denomination circulated coinage in America, did not picture a Native American nor a bovine for that matter. This was the new radical difference that Fraser wanted to pursue in his design for the five-cent piece. Where the sides were slightly concave like gold eagles and double eagles. A truly American design that has not been challenged in over a hundred plus years of minting.
Below is an excerpt from The Numismatist issue of 1913, stating how different this was, and challenging all other designs prior. A push to elevate the look and feel of American coinage at the time.
The design is radically different from that of any five-cent piece that has ever been issued at the Mint, and is slightly concave on both sides, somewhat like the present ten and twenty-dollar pieces. Directly under the figure “3” of the date 1913 on the obverse is the letter “F” for the designer of the piece, James Earl Fraser of New- York City. It is said that Mr. Fraser took as a model an Indian of the Cheenne tribe who recently visited New York City. The bison was modeled after a specimen in the New York Zoological Garden. 
- “The New Five Cent Piece” The Numismatist 1913 pg133.