Had a couple big Black labs from N. Dakota many years ago, The little guy, Bo, was around 130 lbs, The big un, Sport, even our big old mean crotchety bull woundn't take him on. Kinda like two freight trains colliding head on. Place I take my electric motors to for repair has a pair of Blacks- darn right intimidating until you get the tennis ball out.
The Chesapeake bay's are nice too, at around 70lbs. I see your wearing shorts in the dead of winter - must be a wood burner!