As the official Walt Disney mascot, Mickey has played a central role in the Disney parks since the opening of Disneyland in 1955. As with other characters, Mickey is often portrayed by a non-speaking costumed actor. In this form, he has participated in ceremonies and countless parades, and poses for photographs with guests. As of the presidency of Barack Obama (who jokingly referred to him as "a world leader who has bigger ears than me") Mickey has met every U.S. president since Harry Truman, with the exception of Lyndon B. Johnson.