Archaeologists have uncovered a ‘once-in-a-lifetime’ archaeological treasure trove within Wogan Cavern, a massive subterranean chamber hidden directly beneath the 11th-century Pembroke Castle.
While previously dismissed by Victorian-era explorers as empty, modern small-scale excavations conducted between 2021 and 2024 revealed remarkably intact sediment layers. According to the University of Aberdeen, these deposits contain an extensive prehistoric archive, including stone tools and fossils of extinct species like mammoths, woolly rhinoceroses, and a hippopotamus dating back approximately 120,000 years.
Led by the University of Aberdeen, a new five-year, large-scale investigation aims to utilise advanced techniques, such as ancient DNA analysis and high-resolution dating, to map human occupation and environmental shifts spanning over 100,000 years of British history.
A rare prehistoric cave was found beneath a Welsh Castle, yielding rare fossils and stone tools
The discovery of Wogan Cavern is a prehistoric archive of unparalleled importance for British archaeology. This cave can be accessed using a spiral staircase that is part of the medieval castle at the top of a hill, and it contains a very important and relatively rare permanent record of prehistoric life through layers of history.
As noted in a study at the University of Aberdeen, initial analysis values the material contained in this cave to some time between approximately 45,000 and 35,000 years, when early Homo Sapiens were potentially inhabiting parts of Britain, and may also contain evidence of the presence of Neanderthals from before that date.
Because the sediments have been preserved in layers (strata), this cave could provide scientists with an unusual opportunity to consider the effects of climate on the types of ecosystems that existed at different periods of time by studying the animal and plant life through microfauna and ancient DNA.
This discovery is reconstructing ancient climates and prehistoric survival
Scientists have also discovered hippopotamus bones that likely date from the last interglacial period (approximately 120000 years ago) in the sediments of the cave. This may suggest that, in Wales, temperatures have been significantly lower and climate conditions have been much warmer than we previously thought existed there before. The cave contains extensive evidence that reindeer, wild horses, and a wider range of Pleistocene fauna, and may provide an accurate timeline for the transitions in climatic conditions that occurred in Wales.
Ultimately, researchers hope that this data will assist in providing answers about how prehistoric hunter-gatherers survived the dramatic environmental changes that occurred as the last Ice Age came to a close, and as warmer and more temperate climates began to develop across portions of Europe.
Unlocking human history through sediment DNA analysis
The upcoming five-year excavation project, scheduled to start in May 2026, will use advanced scientific methods with the help of the Calleva Foundation and Pembroke Castle Trust. The research team will focus on the analysis of genetic material from sediment, which can identify the presence of humans and animals when no bones are available. Analysing these high-resolution data points should enable reconstruction of the exact sequence of human activity in the area and facilitate advanced understanding of the transition from Neanderthals to modern humans in Britain.
