a wild stallion otherwise known as a bronco
The mascot 4 Denver is broncos
Denver Nuggets-Rocky Denver Broncos-Miles
Thunder
Indianapolis Colts
Winning answer suggested by a fan in a naming contest in 1960. http://www.sportsecyclopedia.com/nfl/denver/broncos.html
Miles' web site has been added to the 'related links' section of this answer.
The college team that has a bronco mascot is the University of Denver. Their mascot, named "Denver Boone," represents the school's athletic teams, known as the Pioneers. The bronco symbolizes the spirit and tenacity of the university's athletes. Additionally, the Western Michigan University Broncos also feature a bronco mascot for their athletic programs.
The Denver Broncos were founded in 1959.
Denver Broncos was created in 1960.
They were named as a result of a fan contest held in 1960.An article that has a brief snippet on the mascot's history in Denver is linked to below.
The Broncos play in Denver, Colorado.
The horse that represents the Denver Broncos is named "Thunder." Thunder is a live blue mustang that rides onto the field during home games to energize fans. The Denver Broncos mascot, "Miles," often accompanies Thunder during games and events. Together, they enhance the game-day experience for fans at Empower Field at Mile High.