8 years ago
I am just going to go with, Xenomorphs evolved just like any other creature. take dinosaurs for an example, sure they're extinct, but, a bird is technically an evolved version. it has been proven that velociraptors had quill knobs on their forearms showing that they indeed had feathers, but were not evolved enough for flight. raptors closest relatives are today's birds. I'm thinking Xenomorphs started life with fully fuctional eyes. as the years went on they evolved past the need for eyes. especially since they spend so much time in the dark. their other senses developed more and their eyes became obsolete. tho they still have remnants of having eyes in the past. (I think that's the right word). I don't remember if this was in the movies or comics, but I have a feeling Xenomorphs can smell better with their mouths open likes cats do. due to special scent glands on the roof of their mouths. That's just an example of stronger senses they use, rather than sight.
sorry for rambling ~X27