it is suggested that the patagonian opossum may have emerged from the same ancestral group as "marmosa". they resemble each other closely. in the winter both types have similarly thickening at the base of the tails, where fat accumulates. yet they do not share all aspects of their lifestyle; patagonian opossums have a specialized way to gather and consume food, which is made possible by the shortening of their skull and jaws. the shortening occurs in the premolar region; this gives the patagonian opossum increased biting power.