In museums around the world, reproductions of Neandertals sport striking blue or green eyes, pale skin, and gingery hair. Now new DNA analysis suggests that two of the most closely studied Neandertals—a pair of females from Croatia—were actually brown-eyed girls, with brunette tresses and tawny skin to match. The results could help shed new light on the evolution of the family that includes both modern humans and Neandertals, who died out some 30,000 years ago.

The study has provoked deep skepticism among several outside researchers, however, who criticize numerous aspects of its methodology. The results also run contrary to other genetic evidence and to a long-held hypothesis that Neandertals, who lived mostly in northern latitudes, must've had light skin to get enough vitamin D....