Pack animal Pack animal A pack animal or beast of burden is an individual or type of working animal used by humans as means of transporting materials by attaching them so their weight bears on the animal's back, in contrast to draft animals which pull loads but do not carry them. Traditional pack animals are diverse including camels, goats, yaks, reindeer, water buffaloes, and llamas as well as the more familiar pack animals like horses, donkeys and mules. The term "pack animal" is traditionally used in contrast to "draft animal", which is a working animal that typically pulls a load behind itself
Girth (geometry) width, with the same width "w". All curves of constant width have the same perimeter, the same value "w" as the circumference of a circle with that width (this is Barbier's theorem). Therefore, every surface of constant width is also a surface of constant girth: its girth in all directions is the same number "w". Hermann Minkowski proved, conversely, that every convex surface of constant girth is also a surface of constant width. For a prism or cylinder, its projection in the direction parallel to its axis is the same as its cross section, so in these cases the girth