User blog comment:Bluegear93/What if there were no Geth?/@comment-95.180.198.19-20111023171735/@comment-2001840-20111023211024

An early iteration of Mass Effect's story featured the batarians as the primary enemies in place of the geth. The batarians were also originally intended to be "small bat-like people".

Source: the Wiki on the Batarians page trivia.