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).
Weight is one ton for $17. I tried to determine how much weight my pickup can haul but when I went to the specs page, I found a whole variety of weights such as curbweight, torque weight etc etc. Here's the site. BTW, I'm using the crushed rock for ballasting my toy train track outside (to a depth of about 6 inches).