Theoretically, there's not a lot different between the roar of a great cat and the scream of a baby — except for volume and pitch.
At least that's according to scientist Ingo Titze's new research into the morphology of lion and tiger vocal cords. Both cats and infants have penetrating and loud cries which carry remarkably far, and that's thanks to their vocal folds, which are loose and gel-like in both cases. Because they're so wobbly, they vibrate irregularly making a dissonant and unpleasant sound.
Top image via Wynner3 on Flickr.
"In both cases, we hear loud, grating sounds that grab people's ears. When a baby cries, the sound isn't pretty. The sound is basically rough. The vibration isn't regular."
The research also showed the the roars are loud and deep due to vocal fold's flat, square shape which can withstand the abuses caused by such volumes — not due to being heavy with fat as previously thought.
So while great cats might have a lot in common with screaming babies, do try not to mix the two of them up — or you could wind up making the zoo very unhappy.