A theory...

Think back to when you first saw alien. do you remember the space jockey that looked like a chest burster came out of it? remember how BIG that jockey was? sooo... The jockey's body has been decaying so long it actually began to look as if it were growing of its seat. erosion and decay like that takes a while. now seeing how big that Jockey was... and how big the queen from avp was..... and the alien takes attributes from its host.... what do u think?