The family primarily consisted of large quadrupedal terrestrial
browsers, notably including the largest marsupial that ever lived, the rhino-sized
Diprotodon. Nimbadon, which is often considered a basal diprotodontid, was
arboreal. Diprotodontids were
plantigrade (foot and toes flat relative to the ground). In most diprotodontids, the forelimbs were not specialised and were capable of being used for functions other than movement. Some later diprotodontids from the Pliocene onwards like
Ambulator and
Diprotodon developed elephant-like forelimbs specialised for walking with modified wristbones which functioned as a
heel, along with the development of footpads, which means that the digits probably did not contact the ground, as evidenced by the lack of toes on footprints of
Diprotodon. In at least some representatives of the clade, the inside of the skull was lightened by large interior
sinus spaces. == Ecology ==