Now We Know Why Britain's 'Oldest Human Brain' Looked Pristine Even After Thousands Of Years

Scientists got a huge surprise in 2009 when they found a well-preserved human brain inside a 2,600-year-old skull dug up at an archaeological site in Heslington, England. They simply couldn't fathom how a mass of soft tissue could be preserved for thousands of years.

But now they know the answer--and it's all about mud.

That's right. Researchers at the York Archaeological Trust have determined that the wet, clay-rich soil in which the skull was found provided a sealed, oxygen-free environment that protected the brain against bacterial decomposition.

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oldest human brain
Rachel Cubitt, of the York Archaeological Trust, uses an endoscope to examine the brain.

"I peered though the hole at the base of the skull to investigate and to my surprise saw a quantity of bright yellow spongy material," Rachel Cubitt, collection projects officer at the Trust and the person who gave the brain a cleaning, said in a written statement. "It was unlike anything I had seen before."

Whose brain was it anyway? The scientists think it belonged to a man between the ages of 26 and 45. The neck vertebrae suggests that the man sustained a hard blow to the neck before his head was severed--perhaps in a ritual sacrifice.