About Yamaha's exaust pipe

I cant but notice how yamaha's exaust is literally nonexistent, is there a reason for this? It's the only bike with a pipe that short, doesn't this affect acceleration/power output?

I cant but notice how yamaha's exaust is literally nonexistent, is there a reason for this? It's the only bike with a pipe that short, doesn't this affect acceleration/power output? http://ifttt.com/images/no_image_card.png