Leo the lion doesn't roar
Did anyone notice that at the start of the film, Leo the MGM lion does not roar? It's just a still of him, making no sound at all. I assume this was done to emphasize the religious theme of the picture, its dedication to peace, the lamb will lay down with the lion, and so on.
To the best of my knowledge only one other film did not show the MGM lion roaring at the start -- BEN-HUR (1959), obviously because of those same basic religious themes in that film. (I don't count "2001", since that used the MGM record label illustration of a lion at the beginning, not the usual, real lion; or MGM's silent films, where the lion is weirdly roaring away, but of course with no sound!)
EDIT nine years later: Per my own trivia entry and as I've been reminded, there is a third 1950s film where Leo doesn't roar: Westward the Women (1951).