Shortly after moving back from Germany (military stepfather), we rescued a female bullmastiff. She was the most gentle dog I've ever met- and I only ever heard her growl or bark once. And it was NOT a 'warm and cozy' sound; even from the safe side of the dog. Roughly 90lbs of 'get off my lawn', and still would let a 3 year old try to ride her like a horse. Best dog ever.