The Anasazi lived in the cliff houses for less than a hundred years. By 1300 Mesa Verde was deserted. Here is another mystery. We know that the last quarter of the century was a time of drought and crop failures. Maybe after hundreds of years of intensive use the land and its resources--the soil, the forests, and animals were depleted.
When the Anasazi left, they may have traveled south into New Mexico and Arizona, perhaps settling among their kin already there. Whatever happpened, it seems likely that some Pueblo Indians today are descendents of the cliff dwellers of Mesa Verde.