On Tue, Jan 25, 2011 at 10:34, John Culling <cullingj@xxxxxxxxxxxxx>
My understanding is that high-frequency hearing is basically
a mammal thing. Even the vaunted auditory system of the
barn owl is limited to 10 kHz. The reason mammals developed
high frequency hearing is probably that they were small
and nocturnal and needed to hear where things were in
the dark with their small heads
I think that the other reason why only mammals possess HF hearing may be that only the mammalian middle ear is capable of transducing them effectively thanks to having 3 ossicles insted of one.
As for the role, Rickye Heffner and Henry Heffner made an argument that it's been primarily driven by the needs of localization. It was based on the correlation of HF hearing range with effective interaural distance (effective, i.e., taking the medium into accout; dolphins have small effective interaural distances).