Quote Originally Posted by WingedWolfPsion View Post
Raptor is entirely correct. Poor breeding (or breeding for illegal purposes) can certainly produce aggressive dogs. Genuinely aggressive, not just dominant.

However, that does not make the breed itself aggressive or dangerous--only the mis-bred dogs themselves. You can do the same thing with mutts--breed aggressive to aggressive, and get more aggressive. No dog breed is actually bred to be aggressive towards people across the board. Even the guarding breeds are carefully bred to be loving and protective of their family, and aggressive only toward outsiders.

The Fox Farm experiments show that temperament is heritable in canines.
Personality is inheritable in general. With my mice, I purposely bred the pairs that didn't bit and would go calm and content when handled, despite no prior handling. I now have mice that once I catch them will happily sit in my hands and clean themselves. I have a buck goat that all his offspring are calm and docile creatures. If you breed two hot tempered horses together, you'll probably get the same with the foal (explains why most horses of a certain breed act similar).

If you breed your animals carefully, there's no reason on why you should get an aggressive animal, with the exception of recessive genetics.