20 Things You Didn't Know About The Xenomorph

In an early draft of the story, screenwriter Dan O'Bannon depicted the creatures as belonging to an advanced and civilised race of aliens who must undertake a period of adolescence that sees them become antisocial and ultra-violent.

Bannon's vision suggested that the kinder, friendlier Xenomorphs would care for the young, to help teach them their peaceful ways. Following a cataclysmic event, the adults were all wiped out leaving the young to turn completely feral. In other words, they're teenagers left home alone for a few thousand years, and that never ends well.