What it says on the tin.

Discuss away.

I don't think so, otherwise all dragons would probably kill each other to grow stronger. I think its only the Dovakiin who can absorb souls.

Actually Arngeir says that dragons can devour each other's souls and get stronger just like the DB does, according to the UESP wiki.

I'd say the reason why we never see any of that is due to the gameplay != lore factor in Skyrim.

Oh my bad then, i didn't know that.. But yeah if they did that, there wouldn't be any dragons left for us to kill

EDIT: Nvm.