Paleohumans, including Denisovans and Neanderthals with ear exostoses, probably lived mostly on marine foods. Sea levels have risen about 120 meters in the past 18,000 years, so most of the coastlines where paleohumans lived are now under water and largely unexplored. This helps explain why there is very little evidence of paleohuman tools, fire, dwellings, and burial of the deceased.