Billy (pygmy hippopotamus)
| Other name | William Johnson Hippopotamus |
|---|---|
| Species | Pygmy hippopotamus (Choeropsis liberiensis) |
| Sex | Male |
| Born | Before 1927 Liberia |
| Died | October 11, 1955 |
| Employer | National Zoo |
| Years active | c. 1930 – 1955 |
| Residence | National Zoo |
| Offspring | 23 calves |
Billy, also known as William Johnson Hippopotamus (before 1927 – October 11, 1955), was a pygmy hippopotamus given to United States President Calvin Coolidge. Captured in Liberia, he was given to Coolidge by Harvey S. Firestone in 1927. Billy spent most of his life in the National Zoo in Washington, D.C. 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 hippopotamuses in American zoos. By the time of his death in 1955, Billy had sired 23 calves, 13 of whom survived at least a year.