Answer:
We are all around, yet to us you are half blind. Sunlight makes us invisible, and difficult to find
What surrounds the world, yet dwells within a thimble?
I hide but my head is outside.
It comes only before, it comes only after. Rises only in darkness, but rises only in light. It is always the same, but is yet always different.
A leathery snake, with a stinging bite. I'll stay coiled up, unless I must fight.
I have two eyes in the front and a lot of eyes on my tail