: You can't breed things for targeted aggression (unless you've mastered and elevated the science of bio-engineering). Its very unlikely that you could breed something to attack its own kind but submit to another species. In fact everything I've read about dog domestication links it to pack mentality the owner replaces the pack (or the pack leader at any rate); So how can you have a creature accept an alien as its pack leader but but retain aggressiveness towards its own species?