Possible Clues:

• Sound of the ocean or a lion
• Item for boat found beside river? Give a cheer
• Pride protest
• "Dark Side of the Moon"/"Wizard of Oz" cue
• There's a whale of a lot of this, by the sound of it
• By the sound of it there's a lot of it for the sweep at last
• Sound before an MGM movie
• Storm sound
• Mimic a tiger
• Hurricane sound