High Quality Content by WIKIPEDIA articles! Billy, or William Johnson Hippopotamus, (1920s – October 11, 1955) was a Pygmy Hippopotamus given as a pet to U.S. President Calvin Coolidge. Captured in Liberia, he was given to Coolidge by Harvey Firestone in 1927. Billy spent most of his life in the Smithsonian National Zoological Park. In addition to his fame as an exotic presidential pet—which afforded him a trip to the 1939 New York World`s Fair—Billy is also notable as the common ancestor to most pygmy hippos in American zoos. By the time of his death in 1955, Billy had sired 23 calves, 13 of whom survived at least a year.