Cattle only yield about 41% pure meat. Hide, guts, bones and whatever else you don't eat make up the other 59%.
Right
I just assumed that a bison would be above that for some reason. But I guess there is a thicker hide on them and maybe even heavier bone.
Bison have substantially less meat yield than cattle. I learned this after shooting several for meat, back when they were more affordable. Their hair is much thicker, and the "hump" on their back is actually mostly hide and bone. If you look at a diagram of their skeletal structure, you will notice the extremely large vertebrae that are present in the hump area (see below). It has always fascinated me that their spines are actually straight, like most game or cattle species. The hump is only a result of the taller vertebrae.