Digging for Neanderthals under a medieval Welsh castle
Unscathed by destructive Victorian-era excavations and modern tourism, Wogan Cavern may provide scientists with a glimpse into the lives of our earliest ancestors.
The rocky cliffs, coves, and rugged coastline of Pembrokeshire, Wales, surround a lush and ancient river valley. Nestled within is the town of Pembroke, which is crowned by the majestic Pembroke Castle, a towering medieval fortress with a storied history: it is the birthplace of Henry Tudor, who became King Henry VII during the Wars of the Roses and the ancestor of the British royal line.
In recent years, researchers have discovered it also has a storied prehistory.
Beneath its 12th-century walls lies a natural chamber gouged out of the limestone bedrock called Wogan Cavern. Many modern historians assumed that Victorian Age excavations had emptied the cavern of its secrets. But digs between 2021 and 2024 have unearthed stone tools and clues of human occupation spanning multiple eras—from Mesolithic hunter-gatherers around 11,000 years ago to early Homo sapiens between 35,000 and 45,000 years ago. They also revealed that the cave sediments are mostly intact and may still contain traces of more than 100,000 years of the past.
Now, a team of researchers has begun a five-year excavation to investigate Wogan Cavern in hopes of gaining a glimpse into the lives of some of the ancient humans who may have resided inside.
“This offers a rare chance to apply new scientific methods to an early prehistoric archaeological cave,” says Robert Dinnis, an archaeologist at the University of Aberdeen in Scotland who leads the project. Unlike many previously excavated caves in Britain, Wogan Cavern has large and intact archaeological deposits to “answer key questions about early prehistory,” he adds.
The research also aims to show how the region changed under a climate that ranged from almost tropical to an Ice Age.
The cavern is “a site of exceptional potential for future work on the Middle and Upper Paleolithic of Britain,” says Chris Stringer, a paleoanthropologist formerly of London's Natural History Museum, who is not involved in the excavation efforts. “It is very likely to yield either physical or genetic remains of both early Homo sapiens and late Neanderthals, but the excavations are at an early stage.”
Prehistoric cavern
Wogan Cavern existed for hundreds of thousands of years before Pembroke Castle was built atop the rock outcrop by the river. For tens of thousands of years, it had been a riverside shelter for animals such as mammoths, woolly rhinoceroses, reindeer and wild horses. In April, the researchers announced the discovery of hippopotamus bones; they are about 120,000 years old and indicate that Britain was semi-tropical at the time.
There are even hints that the cavern was inhabited by Neanderthals, perhaps 60,000 years ago. The preservation of the organic material found so far means that precise radiocarbon dating is possible; and pilot studies show ancient DNA is preserved in the cave sediments themselves, as well as in bones. This wealth of genetic material could let scientists reconstruct entire past ecosystems from the sediments and better understand how early humans adapted to environmental changes.
(A look inside the world of the Neanderthals)
“It feels inevitable they are going to find something tantalizing,” says Thomas Booth, a geneticist and archaeologist at the Francis Crick Institute in London.
“Wogan Cavern lies at the periphery of the Eurasian landmass, the edge of the world, and at certain times [it was] just shy of the greatest extent of the Northern European glaciers,” he says. “I have no doubt that there are some compelling stories of human resilience waiting to be uncovered.”
Cave sediment sampling
Medieval and later inhabitants of Pembroke Castle used the cavern for storage, fitting it with iron bars to prevent access from the river (though they are no barrier to the greater horseshoe bats that roost on the cave ceiling).
Tourists can visit Wogan Cavern by descending a spiral stone staircase from the castle, though the latest excavations sometimes made it unsafe to visit, says archaeologist Jonquil Mogg, a researcher and collections manager at Pembroke Castle. They plan to build new facilities to display the finds from the cavern.
Though the project's prehistoric focus is a departure from the castle’s medieval history, any finds will provide a whole new aspect to the site's heritage, says Mogg.
"It's important for us, and for the people of Pembroke,” she adds.
Nick Ashton, a paleolithic archaeologist at the British Museum, says Wogan Cavern had escaped the "cleaning" for tourists that has destroyed the archaeology in other caves in Britain.
“Unlike many of the caves from this period that were emptied of most sediments to present as showcases in the late 19th or early 20th centuries,” he says, “Wogan seems to have intact deposits that deserve a detailed program of excavation.”
Dinnis says that the team's most recent work examines sediments from part of the early Holocene period, between about 11,000 and 10,000 years ago. Afterward, the scientists will excavate older deposits. But the five-year project, he says, will provide the researchers with only enough time to analyze a small part of the cavern's deposits. Dinnis adds, "I’m sure Wogan Cavern will see ongoing research for decades and centuries to come."
