12 years ago
It's been said that in times of crisis, a grey, or lone drone, would take a hostage and turn it into a specific egg through substance injection with the tail. That egg in turn creates what we know as the Superfacehugger, and it's there that we can tell for sure why a Queen is so "special". For some reason, one of the eggs the Superfacehugger carries is much different and special than the others it carries and the other ones of the hive.
It doesn't happen by chance. We don't know for sure yet why, but that embryo turns into a Queen, which, for some reason, is supposedly female and never takes the personal traits of its host. However, we can't say that for sure - techically we've only seen a Queen created from a human. The Queen in AVP was most likely created by one of the ancients and the one in Resurrection was like a bad translation of english to Chinese back to english.
Queens are only created when there isn't one already in control. A Queen does not take the traits of it host so Predqueens aren't possible. And you can't have gorilla Aliens or eagle aliens or whatever - notice that, although the Dogalien DID take on the quadruped state, it just looks like a regular human alien, but on all fours, and with a much smaller head (also the tubes on its back are missing). No larger teeth, no ridiculously enlarged muscles or the need to walk on its knuckles, it just ran on all fours. Imagine a human doing that. Other than the fact that a human running on all fours looking like a dog is ridiculous, he still looks like a human.
There have been four types of Queens in the movies, only one taking on the traits of its host. The one in Aliens was a normal Queen, the one in Resurrection a human-thing, the one in AVP an Empress, and the one in Reqiuem a sick piece of shit Predalien.