- Fake Irish: John Wayne as Sean Mercer.
- Fake Nationality: Luis (actor born in New-Mexico) as a Mexican. Also, the Indian is not played by a Native American. However, Kurt is played by a German actor, Chips and Brandy are both played by French actors, Dallas is played by an Italian actress, and Red Buttons was indeed a New-Yorker.
- Looping Lines: Much of the action sequence audio had to be re-dubbed due to John Wayne's cursing while wrestling with the animals.
- Technology Marches On: The method of capturing animals shown in the film is legally prohibited nowadays, due to possibility of injuring and even killing animals. Tranquilizers and dart guns are used instead.
- Throw It In!: The rhino in the second chase really did escape, and they just kept the cameras rolling and caught it again.
- What Could Have Been:
- Clark Gable had agreed to star in the movie with John Wayne, provided he received first billing on the opening credits, and one million dollars, plus ten percent of the gross. Paramount, however, would not raise the budget to finance Gable, so the script was radically changed. Gable died twelve days before filming began.
- Howard Hawks was keen to pair up William Holden, a keen conservationist, with either John Wayne or Gable.
- The role of Pockets was originally an Englishman named Robbie and Hawks offered the role to Leo McKern, Peter Ustinov and Peter Sellers. McKern refused to work with the Right Wing Wayne, Ustinov was unavailable and Sellers accepted before the character was reworked into an American.
- Writing by the Seat of Your Pants: Shooting started without a complete script. Writer Leigh Brackett was hired at a later date to retrofit the animal footage into a cohesive storyline.
Trivia / Hatari!