For the roar of Godzilla, I took out the lowest string of a contrabass and then ran a glove that had resin on it across the string. The different kinds of roars were created by playing the recording of the sound that I'd made at different speeds. Toho's sound engineers previously had tried to use the roars of many different animals for Godzilla's roar. They went to a zoo and recorded the roars of many different mammals, but no matter how the sounds were manipulated, they seemed too much like the roars of each of the animals. The sound engineers also tried to alter the call of a night heron bird, but that also was not successful.

As quoted by David Milner, "Akira Ifukube Interview I", Kaiju Conversations (December 1992)