I'm a freak!!!
You are a dog
Or maybe you are a mosquito, you certainly can't be human.
The highest pitched ultrasonic mosquito ringtone that I can hear is 21.1kHzFind out which ringtones you can hear!
Well we all know that I"m a mutant anyway, this just cements the fact even further *snigger*
*EDIT. I just turned my speakers up and realised I could hear the next one as well. Trouble is now I have a tooth ache lol.