He is 23 inches tall and weighs around 78 when he is lean and in good shape. He has lost mass because I haven't had time to keep him working with the arrival of my son. He gets protective at night in our backyard. He is a fan of people, he is a canine good citizen but I can bet money if someone went near my wife or son the wrong way they would get his wrath. When I am not home he is very alert and takes over, however, he is very stable and has never shown any unprovoked agressive body language.