The MGM trademark lion, Leo, famously roars at the beginning of every MGM film. In fact, "Leo" has not been one lion but seven, starting with "Slats" the lion from 1917 to 1928. An actual lion named Leo roared from 1957 to the present day.

"Jackie," born in 1915, was the second MGM lion and the first celebrated roar. The roar was recorded separately and then married to a film of Jackie roaring, with Jackie's head in a frame to give a black surround. The final product was first used in MGM's first sound production, White Shadows in the South Seas (1928). The sound was provided to the studio microphone by a gramophone record.

It is Jackie and his roar that is seen in sepia at the beginning of The Wizard of Oz (1939). As well as being MGM's living logo, Jackie's also appeared in over 100 films, including several Tarzan movies.