Dry stone from the arable or cultural land. They serve both as cattle/sheep fences and the lot's borders. Sometimes also the dry stone terracing is apparent, often combined with parts of stone masonry (house foundations and shed walls) that are held together by a clay-cum-needles "composite" mortar. In Peru in the 15th century AD, the Inca made use of otherwise unusable slopes by building dry stone walls to create terraces. They also employed this mode of construction for freestanding walls. Their ashlar type construction in Machu Picchu uses the classic Inca architectural style of polished dry-stone walls of regular shape. The Incas
Machu Picchu who performed heavy physical labor (such as the Mit'a) and/or served in the Inca military. Not only people were suspected to have immigrated to Machu Picchu, there were several animal bones found that were not native to the site. Most animal bones found were from llamas and alpacas. These animals naturally live in altitudes of 14000 ft above sea level rather than the mere 8000 ft Machu Picchu rests on. Most likely, these animals were brought in from the Puna region for meat consumption and for their pelts. Guinea pigs were also found at the site in special burial caves,