Marine resources exploitation between Final Pleistocene and Early Holocene (25 – 9 cal kBP). Data from an inland mid-mountain site: Coves de Santa Maira (Valencia region, Spain, Western Mediterranean)

Deep in the mountains of eastern Spain, far from the sea, a cave holds a secret about how ancient people lived when the world was very different. For thousands of years, humans have relied on the land around them for food, but they also looked to the water. The story of how early hunter-gatherers in the Mediterranean region used the ocean is often incomplete. Many of the ancient camps built right on the shoreline have vanished, swallowed by rising seas that have pushed the coast back over millennia. This leaves archaeologists with a puzzle: how did people living deep inland access the sea, and what did they do with the fish and shells they brought back? To solve this, researchers must piece together the changing shape of the coastline and the tiny, scattered remains left behind in caves like Coves de Santa Maira.

A team of scientists recently turned their attention to this very cave, located in the Valencia region. The site sits high in the mountains, roughly thirty kilometers from the modern shoreline. However, the world was not always as it is today. Between twenty-five thousand and nine thousand years ago, the climate shifted dramatically, causing sea levels to drop and then rise again. By reconstructing the ancient geography, the researchers found that during the coldest part of the last Ice Age, the coastline was actually much farther away, nearly sixty kilometers from the cave. As the climate warmed, the sea crept closer, shrinking that distance to about forty kilometers. The team sifted through layers of sediment in the cave, looking for the bones of fish and the shells of mollusks, to see how human behavior changed as the distance to the ocean varied.

What they found was a clear story of adaptation. In the deepest, oldest layers of the cave, dating back to the peak of the Ice Age, the evidence of marine life was scarce. The few shells and bones found here were mostly used as decorations. The people who lived there, known as Solutrean, carried shells from the distant coast to make beads and pendants, but they did not seem to rely on the ocean for their daily meals. The journey was too long, and the resources too difficult to transport in large quantities. Instead, these early inhabitants focused on the land and the rivers nearby.

As the climate warmed and the sea level rose, bringing the coastline closer, the story in the cave changed. During the later periods, known as the Late Glacial and the Early Holocene, the amount of marine food found in the cave increased significantly. The people living there, now identified as Magdalenian, Epipaleolithic, and Mesolithic groups, began to bring back far more fish and shellfish. They were catching a variety of sea creatures, including mullet, sea bream, and eels, often in the shallow lagoons and river mouths that formed where the Gorgos River met the sea. These fish were not just occasional treats; they became a regular part of the diet. The researchers identified hundreds of fish bones, showing that these groups were skilled at catching both small and medium-sized fish in the coastal wetlands.

The way these people used the shells also evolved. In the earliest times, shells were almost exclusively ornaments. But as the sea came closer and the catch became easier, the shells took on new roles. The researchers found that people began to use the hard shells of mussels and other bivalves as tools. They shaped them into scrapers and smoothers, using them to work on animal hides and plant materials. Some of these tools were even used with ochre, a natural red pigment, suggesting they were part of complex daily tasks like preparing clothing or creating art. This shift from using shells only for beauty to using them for practical work shows how human groups adapted their technology to the resources available to them.

The study also revealed that the people of Coves de Santa Maira were not just passive observers of their environment; they were active travelers who understood the landscape. By analyzing the types of fish and shells found, the team could tell exactly where the resources came from. The presence of specific species indicated that the groups were traveling to the river mouths and coastal lagoons, areas that are now underwater. The fact that they brought these resources back to a mountain cave, sometimes traveling over forty kilometers, proves that they had a sophisticated understanding of the region's geography and the seasonal movements of marine life.

This research fills a significant gap in our understanding of prehistoric life in the western Mediterranean. For a long time, this area was thought to be on the edge of the story of early human adaptation to the sea, with most evidence coming from southern Spain. The findings at Coves de Santa Maira show that even in the mountainous interior, people were deeply connected to the ocean. They did not just visit the coast; they integrated its resources into their lives, changing how they ate, what tools they made, and how they decorated themselves as the world around them changed. The cave stands as a testament to human resilience and ingenuity, showing how ancient groups navigated a shifting world to survive and thrive.