Board Thread:Lore Discussion/@comment-2165692-20140425203121/@comment-2A02:587:C431:F500:D91B:7526:3000:16A5-20171001182102

Perhaps they get blindsence... like sonar or something, so technically yes, they hear cliffs (or, more preciesly, the echo of the cliffs.

Perhaps they learned this trick from the Chorous, a giant insect that seems to be the most important part of modern falmer culture, and their mages learned to replicate the sonar hearing through magic, and as time passed, it became a racial spell to them (like Flames is to Dunmer for example)... Falmer are Elves after all, and magic comes naturally to them.

As years passed, this "racial spell" was more reliable to them in the dark than their sence of sight, so they evolved to blindness, relying only to this sonar to locate things.

-A fan theory based piece of lore by Manuel/Asmo