I can't help getting annoyed at anything showing "unexpected etymology" that ignores key elements of the structure of words. Fledermaus isn't a cognate with mou

I can't help getting annoyed at anything showing "unexpected etymology" that ignores key elements of the structure of words. Fledermaus isn't a cognate with mouse, it's that the German word for bat is "flying mouse" (compare English flying fox for a type of big fruit bat).