The bite force of a boerbole is so strong that they must not use standard body protection while training them ,, the boerbole mastiff can bite through armor that is ok to be used training a rotty. Boerbole mastifs have been known to overpower and kill healthy adault hyenas,,a rotty would be a meal for … Read more

French mastiff is real high on the list as is all mastiff breads ,,great danes and irish wolf hounds would surprise a lot of people if tested,, those russian herding molossers and the korean fighting mastiff would all do great ,, my money goes on the tibetin mastiff or the mongolian mastiff