Mules are slightly smaller than their horse parent, and when they grow they share traits of both a donkey (the long ears), and the horse (color, tail, etc.). A Mule in the grass.
For example, a 2014 Ford F-150 is considered a half ton truck but most variants can carry a lot more than 1,000 pounds in the bed. Since these terms are probably not going away any time soon, it's best just to think of them as smaller, mediumest, and more than medium.. (Pause for laughter).
A typical half ton truck (chevy 1500, ford f-150, etc) weighs anywhere from 2.25 tons to 2.75 tons (4500-5500#). Of course extended cab, regular cab, and crew cabs account for this varying weight. Next you have 3/4 ton trucks (C20, 2500, f-250, etc). Again, they can be long bed, short bed, extended cab, crew cab, etc.