How does Gollum see in the dark?

I was spelunker for almost ten years. If you turn off the light in the cave only what you can see is darkness. That is really interesting experience. It is not that you see nothing. You see darkness. (I don't believe anybody has ever seen "nothing". How can you see "nothing"?) It is the same as you look at your eyelids from inside in the dark room. But you have eyes open. That's weird. Immediately surrounding space become infinitive and (or should I say: therefore) claustrophobic. You feel that your heart has shrunk somehow (only if you haven't start to panic and treat yourself with panic attack, then started to scream and finally lost consciousness so the rest of the team must carry you outside :-)). Actually, you don't know what to think while you are immersed in blackness. You can wave with your hand in front of your nose but you won't see your hand. You can only feel cold breeze. Or hear dripping of water in the distance. Sounds are amplified by silence and from automatically shift to sense of hearing. It's dark like in a deepest pit in the midnight on the moonless night. :-) Once I was locked in the refrigerator car for a 10 to 15 minutes just to drive me from a point A to point B (I remember how hooks for meat are clanking on the bumps on the road) – it's the same darkness. So, if you want to experience that kind of darkness you can lock yourself in a freezer. It's little warmer in caves but darkness is the same.

So then, how does Gollum see in the dark? If you ever asked yourself that question, here are some answers from Wired Sience.