Students find ring tone adults can't hear

Students find ring tone adults can't hear - Yahoo! News (AP)

Have you heard this yet? Or rather, not heard it?

It's humbling, frankly. Makes one feel old.

My son has this spooky ringtone mentioned above. My husband can't hear it; I can, but just barely (it's almost as if I'm imagining hearing something...).

Animals react to it. At least my son's girlfriend's cat can clearly hear it, reacting to it (wondering where it's coming from).