This week, we were to sculpt a pelvis, pair of femurs, tibias, fibulas, and feet for our Imaginatomy creatures. The pelvis is an incredibly difficult bone to sculpt, especially when it is so different from a human pelvis. All the bones and landmarks are the same, but their arrangement is fundamentally different in quadrupeds. Carl's pelvis is based on that of a rhino, who has a rather vertical pelvis. It's a fun challenge. Because he is inspired partly by the elephant and the rhino, he actually walks on the tips of his toes. Elephants and rhinos (and other ungugrades, or toe-walkers) have a fatty cushion under the arch of their feet, and only the tips of their toes reach the ground.
But, anyway, it looks like he has pants on, and my wife referred to them as "bone pants," so the name stuck. I think he may get a bone shirt next week.