Potatoes Sprouting in the Dark?

While I was getting something from the cold room, I noticed that the newspaper covering the potatoes was sticking out a bit.

When I lifted up the papers I saw this!!  Mostly the russian blue potatoes, but also some of the red chieftain, have sprouted.  In the dark!

I'm not really clear on how this happened; I assumed light was needed to sprout - or at least to sprout as much as this - but the cold room is completely dark (well, I've never actually stood in the room with the door closed and the light off because that's just creepy - but I assume it's completely dark).  I may have to purchase some containers and bags of soil this weekend and get some planted.  Clearly there is no chance of planting in this yard any time soon ...