A shelter at the end of an ice age
Agua de la Cueva is a rock shelter in the Andean foothills of Mendoza that contains a detailed record of human life across the Pleistocene-Holocene transition. The oldest layers of human occupation date to between 11,000 and 10,000 radiocarbon years ago. This period corresponds with the end of the last ice age, when the climate was warming and the landscape was populated by a range of massive animals, known as megafauna, which have since gone extinct.
The primary evidence for these early hunters is their distinctive stone tool technology. Archaeologists have recovered projectile points known as Fishtail or Fell points. These artifacts are a clear marker of Paleo-American populations and are found from southern Mexico to the tip of Patagonia. At Agua de la Cueva, these points are associated with the remains of extinct megafauna, showing that the shelter's inhabitants hunted these large animals. The points were skillfully crafted from materials like chert and attached to spears, possibly used with spear-throwers to bring down prey like giant ground sloths and heavily-armored glyptodonts.
A story of adaptation
The stratified deposits at Agua de la Cueva capture a moment in time; they record long-term adaptation. As the climate continued to warm into the Holocene epoch, the megafauna disappeared from South America. This extinction event forced a complete change in the subsistence strategies of the people living in the region.
Later occupational layers at the site show this shift clearly. The large Fishtail points, designed for hunting massive prey, vanish from the archaeological record. They are replaced by different, often smaller, projectile points. This new toolkit was adapted for hunting the modern fauna that came to dominate the landscape, primarily the guanaco (Lama guanicoe), a wild relative of the llama. This technological change demonstrates how human populations successfully adjusted their hunting practices as their primary food sources changed, resilience in stone and bone within the shelter's floor.