In order
for a creature to become bipedal, there are several traits that must be altered
by evolution first. For example, the foramen magnum must move forward to
straighten the spine, and the skull must become more balanced on the spine. The
feet have to be changed so that they can support the new body style. Then the
pelvis needs to be shorter and wider, the rib cage must be narrower, and we
need longer legs, as well as a few other changes.
