I have been told that the south American buff have the biggest bodies, but the smallest horns, I suspect all the true buffalo(not bison) have about the same temperement. It just depends on how much they get harassed for their attitude at the moment. The cape buff bulls average about 1800#'s but that can vary on area there are smaller varieties in some places. Most of the cape buff are not aggressive at all, but if they are in an area where they are being harassed a lot by poachers, lions etc. they can very short tempered. The Aussie waterbuff bulls average 2200#'s and grow the biggest horns of any horned animal. I have seen several that were more than six feet tip to tip. They also can vary quite a bit in body and horn size, they were imported from several different countries and of course the areas they are in vary also. Most of the time they are not aggressive, like cape buff, but you can never trust them, bulls or cows, we have had quite a few at this point, make flat out charges and some of them were totally unprovoked. A guy was killed by a buff while checking his well near Gove not long ago.