Leo the Lion is the mascot for the Hollywood film studio Metro-Goldwyn-Mayer, featured in the studio's production logo.
Since 1924 (when the studio was formed by the merger of Samuel Goldwyn's studio with Marcus Loew's Metro Pictures and Louis B. Mayer's company), there have been around five different lions used for the MGM logo.
Arguably the two most recognizable MGM lions today are Tanner, the third MGM lion, and the current, unnamed fifth lion. Tanner was used on all Technicolor films and MGM cartoons (including the Tom and Jerry series), and in use on the studio logo for 22 years (the current lion has been in use since 1957, a total of 50 years and counting). However, when the MGM animation department—which had closed in 1958—re-opened with new Tom and Jerry shorts in 1963, these shorts used Tanner in the opening sequence rather than the current lion, which had already been adapted onto the studio logo and the 1961-63 Gene Deitch cartoon logos.