Humans can do that too
I belive it's called synesthesia, you can get it from drugs![]()

Good point, I forgot about that. I thought that is was just something misfiring in the brain and an interpretation rather than a direct sense, though?![]()
As for what the OP is on about, you'd need a hell of an ATU for that
What?

This reminds me of a drunken conversation I had a while ago where I pondered whether alien species could perceive things differently to us, and whether they could possibly "see" what to us is the audible spectrum. I ended up with a sore head (not least because of the beer)![]()