From: The Big Nowhere
As far as I can tell, race family (Humanoid, insectoid, rodent etc) only affects racial bias. Since race bias settings can now be modified, this renders the race family type less important.
I have found however, that when encountering an independant colony, the racial bias settings don't seem to apply. The original race family bias (+10, 0, and -10) is the default for this. If I'm correct, and I think I am, this needs to be changed.
Actually the specific race friendliness is the biggest factor determining whether a race will allow you to colonize or not.
For example, I have a humanoid race independent in my games and I play human. However, the race is very unfriendly (Friendliness = 75). I have never been able to peacefully colonize this race, despite the natural +10 bias of 2 humanoids.
Distant Worlds Fan
'When in doubt...attack!'