The Red Deer Cave People were the most recent known prehistoric Hominin population that did not look like modern humans. Fossils dated to between 14,500 and 11,500 years old were found in Red Deer Cave and Longlin Cave in China. Having a mix of archaic and modern features, they are (tentatively) thought to be a separate species of humans that persisted until recent times and became extinct without contributing to the gene pool of modern humans. Evidence shows large deer were cooked in the Red Deer Cave, giving the people their name.
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Deborah Smith (2012-03-15). "Scientists stumped by prehistoric human whose face doesn't fit". Brisbane Times. Can be read here.
Barras, Colin (2012-03-14). "Chinese human fossils unlike any known species". New Scientist. Can be read here.
Curnoe, D.; Xueping, J.; Herries, A. I. R.; Kanning, B.; Taçon, P. S. C.; Zhende, B.; Fink, D.; Yunsheng, Z.; Hellstrom, J.; Yun, L.; Cassis, G.; Bing, S.; Wroe, S.; Shi, H.; Parr, W. C.; Shengmin, H.; Rogers, N. (2012). Caramelli, David, ed. "Human remains from the Pleistocene-Holocene transition of southwest China Suggest a complex evolutionary history for East Asians". PLoS ONE. 7 (3): e31918. Can be read here.