just found this
Mastiffs can be timid at 10 weeks as you say, but in some cases they can be bold at ten weeks and turn timid, even neurotic, at 10 months.
It seems somewhat like the phenomenon that I have heard about in pet wolves, who of course did not have this behaviour bred into them, but did not have it bred out through centuries of domestication, like many breeds.
At some level Mastiffs are not entirely "in the home" dogs, but have a heritage of being bandogs and war dogs. They mostly are sweet, but can reach very ancient depths. The Mastiff of even 200 years ago was not a pet, and even though today it is the best-natured of the mastiff breeds, is still not always a giant lap dog. I actually don't recommend the Mastiff for anyone who is looking for a big cuddly toy.
They are emotionally complex, and in 28 years of owning the breed, I have never had two alike.
okay.. this helps.. this mastiff is NOT like any other dog I've ever been around... think this might be the clue : The Mastiff of even 200 years ago was not a pet
