Will humans and animals be harmed by frequencies outside their hearing range?

The human ear (for example) is sensitive to frequencies from 20Hz to 20kHz. Any sound beyond that limit would not be heard by us naturally.

1. 
   

   Will it harm us (effect our ability to hear) when we hear sound more than 20kHz continuously?

   
   

   Or...

   
   


2. 
   

   Will it harm when we hear a 19,999Hz sound (which is upper limit) continuously?