Today the term is often used in conjunction with prehistoric or ancient historical references. The mounds contain evidence of prehistoric occupation. Archaeologists have discovered that knot tying dates back to prehistoric times. Artifacts dating back to prehistoric Egypt have been found on Elephantine. These figurines are recognised as some of the earliest works of prehistoric art. They are some of the earliest works of prehistoric art. Archaeoacoustics is studied by testing the acoustic properties of prehistoric sites, including caves. The origins of painting in Japan date well back into Japan's prehistoric period. It was a trade treasure used by the inhabitants of the prehistoric time. Humans have been eating beef since prehistoric times. Negrito groups were the first inhabitants to settle in prehistoric Philippines. Aberdeenshire has a rich prehistoric and historic heritage. See the genus accounts for prehistoric species. Human sacrifice was practised in many human societies beginning in prehistoric times. Xenacanthus is a genus of prehistoric sharks.