The Dogue de Bordeaux is an immensely powerful mastiff-type guardian. Males can go 27 inches high and 110 pounds. The short, eye-catching coat is a richly colored fawn. The massive head features a Bulldog-like undershot jaw, expressive eyes, and a deeply furrowed brow. It is, proportionately, the largest head in the canine kingdom.
#2 – Newfoundland. What looks like a large teddy bear is a dog called a Newfoundland. The heaviest recorded Newfoundland was 260lbs. and over 6 feet long! That’s quite a gentle giant! #3 – Neapolitan Mastiff. Neapolitan Mastiffs are very large dogs in the 170-200lb. range.
The St. Bernard or St Bernard (/ ˈ b ɜːr n ər d / or / b ər ˈ n ɑːr d /) is a breed of very large working dog from the western Alps. They were originally bred for rescue at the Great St Bernard Pass on the Italian-Swiss border, and Little St Bernard Pass in the Italian-French border, located close to one another.
Some dogs may attack or try to dominate other dogs even if they're love-bugs with people; others would rather play than fight; and some will turn tail and run. Breed isn't the only factor; dogs who lived with their littermates and mother until at least 6 to 8 weeks of age, and who spent lots of time playing with other dogs during puppyhood, are more likely to have good canine social skills.