3. Re: What is a natural sound?

["Marc Myers" primatemarc]

In a number of ways. The evolution of the noise regulation, for example. 
Organizing the rhythm of work around very loud sounds like jack hammers for 
another. As a person who grew up in New York I rely in part on the traffic 
noise to tell me something when and where to cross the street. Cities are 
largely monotypic but that single species does produce a fair amount of 
cooperative sound. Also there's no requirement that any soundscape have any 
cooperative sounds.