Between Tarzan Escapes (1936) and Tarzan Finds a Son (1939) MGM let the rights to Tarzan slip into the hands of producer Sol Lesser, who had been trying to get a hold of the property for quite some time.
Tarzan and the Mermaids would be Johnny Weissmuller’s twelfth and last outing as Edgar Rice Burroughs legendary Ape Man. Producer Sol Lesser, feeling that Boy had grown too old for the part of a Jungle Boy, had given Johnny Sheffield the boot after Tarzan and the Huntress, and he also moved the production to Mexico…
With Tarzan’s Desert Mystery the series continues with the Ape Man’s jungle adventures for the war effort. Now Tarzan isn’t going out of his way to engage the Axis powers, they just keep crossing paths, and when you try and cross Tarzan it doesn’t matter who you’re working for, he will take you down.
Tarzan and the Trappers is the result of producer Sol Lesser trying to get a Tarzan television series off the ground, but when all three networks turned it down he had the three pilots edited together as one 70 minute black and white movie.