So I just caught a Noibat and I realized something.

The three first-stage bat pokemon Zubat, Woobat, and Noibat each seem to focus on a certain facial feature.
Zubat and Golbat have extremely large mouths, Woobat and Swoobat have over-sized noses, and Noibat and Noivern have big ears.

Just thought I'd see if anyone else noticed this.