Re read the post. Dogs can be selectively bred FAR MORE EASILY AND TO A MORE EXTREME DEGREE THAN ANY OTHER MAMMALIAN FAMILY. I can get a generic dog and produce a great dane or a chihuahua in 20 generations by selective breeding. You can't do that with cats, pigs, donkeys or people. You can only do it with dogs. Scientific fact.
Are great danes smarter than poodles or French bulldogs? I've never seen any real proof that they are. Do they have different behaviours? Yup. Because great danes are physically larger and the physics of being a large dog and the psychology of being a large dog are different than the same aspects of being a chihuahua. The chihuahua is more excitable - because it's scared a lot of the time - and it runs around a lot more because moving that great dane body takes a lot of energy.
I can accept that some animals are more mutatable than others, but that's different from saying that they cannot be selectively bred. In humans, it's called eugenics.

