Incidentally, although the Cistercians did much to improve the quality of sheep, the animal remained much smaller than its modern descendants; as late as the early eighteenth century a sheep wasn't much bulkier than a Labrador Dog. - Clarissa Dickson Wright
And evolution wasn't even properly invented until the late 1800s. Is that enough time to get a Labrador retriever from a dire wolf? I think not. - Bobby Henderson