Trilobites: The Evolution of the Eyebrow


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A new study suggests humans evolved more mobile, expressive eyebrows to accommodate our increasingly complex relationships.

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AF archive/Alamy

Eyebrows have become an obsession of late, tattooed or microbladed, shaped and drawn in bold dark lines, making a statement far beyond braiding or waxing.

Lifting one and not the other often signals disbelief, amusement, curiosity. Raising both can suggest surprise or dismay. But it wasn’t always that way.

Early humans had thick, bony brow ridges that were far less nimble than ours, incapable of expressing much of anything beyond, “Don’t mess with me, Thag.”

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University of York researchers used 3-D engineering software to look at the brow ridge of a fossilized skull of an archaic hominin, Homo heidelbergensis, who lived between 600,000 and 200,000 years ago.

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Paul O’Higgins/Agence France-Presse — Getty Images

Scientists have long thought those brows served some structural purpose, like support for chewing prehistoric food. That they could also be used to signal aggression or intimidate competitors was largely dismissed as an evolutionary perk, as were the more flamboyant brows of modern humans.

But when Ricardo Miguel Godinho, an evolutionary anthropologist at the University of York, made digital recreations of a skull believed to be 300,000 to 125,000 years old, he found no evidence that its brow ridges provided any of the practical benefits suggested by earlier studies. “He tested out the different possible explanations, and, effectively, there’s no reason for it,” said Penny Spikins, an anthropologist who conducted the study with Dr. Godinho.

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