Lon Chaney Jr. designed his own makeup for Akhoba, but couldn't use it owing to Cosmetician's Union rules.

According to an article in the New York Times on 21 April 1940, D.W. Griffith, who worked as producer on the film, had his name removed from the credits because of a disagreement with Hal Roach. He said "Mr. Roach did not feel that it was necessary to give the characters as much individuality as I thought was needed, and so I did not wish to appear responsible for the picture by having my name on it."

In order to get the lizards to move, heaters had to be turned on full blast because reptiles don't move in cold weather.

Originally, D.W. Griffith was supposed to direct the film. However, he quit in the middle of filming so Hal Roach and his son completed the project.

The #1 Box Office attraction of 1940 (excluding the roll over receipts for Gone with the Wind).

The special effects were so good that special effect footage from this film was used in numerous other films produced well into the 1960s.

When the film was released in Britain, it was heavily edited due to their strict laws against animal cruelty.