 Complete the following phrase:  Doedicurus was likely a grazer, but its teeth and mouth, like those of other glyptodonts, seem unable to have chewed grass effectively, which may indicate a slow metabolism. Doedicurus existed during the Pleistocene. Before this, South America had been isolated from the rest of the world, but the formation of the Isthmus of Panama allowed North American fauna to invade South America in the 