Tarzan Roar

I received a nice email regarding British humor. I like some of the cartoons the rest you may find here. As a kid Tarzan's movies were great adventures eh? so I fetch here Johnny Weismuller one of the most famous Tarzan actors.
 
How was Tarzan's roar created?

 

Now more Jungle cartoons.

Okay lets take a break, I need to go to the restroom were I found that scene....