Chiquihuite cave facts for kids
Chiquihuite Cave is a possible very old archaeological site in the Astillero Mountains, located in Zacatecas State, Mexico. This cave might show that humans were in the Western Hemisphere much earlier than we thought, possibly as far back as 33,000 years ago. The cave is very high up, about 2,740 meters (9,000 feet) above sea level. Stone tools found here have been dated to about 26,000 years ago. Scientists found these dates by testing animal bones and charcoal found near the tools. However, there is still some discussion among experts about whether these stone objects are definitely human tools or if they were formed naturally.
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Exploring Chiquihuite Cave
When Digging Started
Scientists began digging at Chiquihuite Cave in 2012. They started with a small test pit and found some unusual stone objects. This discovery led to bigger digs in 2016 and 2017.
Who Led the Excavations
The main person in charge of the digs was Dr. Ciprian Ardelean from the Autonomous University of Zacatecas in Mexico. His team carefully uncovered 1,930 stone tools from inside the cave.
How Scientists Dated the Finds
To figure out how old the tools were, the researchers used special methods. They took 46 samples of bone, charcoal, and sediment and used radiocarbon dating. This method measures how much carbon-14 is left in old materials to find their age. They also used luminescence dating for six more samples, which tells how long minerals have been buried. These tests showed that the tools were used and left behind about 26,000 years ago. The team also studied pollen and DNA from the cave to look for more signs of early humans.
Signs of Ancient People
Tools and Their Clues
Many of the stone objects found in Chiquihuite Cave look like tools made by humans. Almost 30 percent of them show signs of being used around their edges. These tools are made from black and green limestone. This is important because limestone isn't naturally found inside the cave. This suggests that early humans chose this material and brought it into the cave. The way many of these objects are shaped also suggests they were made by humans. They look like they were chipped or "flaked" using other tools, perhaps made of wood or bone. Dr. Ardelean believes some of these tools are "transversal points," which means they were made using a special method called microlithic technology. This makes them different from tools found at other nearby sites.
Environmental Clues
Scientists also looked at the environment inside the cave. They found tiny plant parts called phytoliths from palm trees in all the samples from the cave. It's very unlikely that palm trees grew naturally at such a high altitude. This suggests that early humans might have brought these plants into the cave.
Animal DNA in the Cave
The team found DNA from many different animals in the cave. These included black bears, rodents, bats, voles, and even kangaroo rats. DNA tests showed that an ancestor of the American black bear was in the cave 16,000 years ago. An extinct giant short-faced bear was there 13,000 years ago. No human DNA was found, but this doesn't mean humans weren't there. It's often hard to find human DNA in very old sites.
How Humans Used the Cave
Since there isn't a lot of other human evidence, archaeologists think that groups of hunter-gatherers only visited the cave sometimes. Perhaps they used it as a safe place during very bad weather. Evidence suggests the cave was used for about 16,000 years. If this is true, Chiquihuite Cave shows that humans learned to live in high mountain areas much earlier than scientists previously thought.
Other Ancient Sites
Similar Finds in Mexico
Scientists involved in this research say that other recent studies have found good evidence of humans in different parts of Mexico. This includes the northwest region, the Chiapas Highlands, Central Mexico, and the Caribbean coast. This new research suggests that humans might have spread into this region as early as 33,000 to 31,000 years ago.
Sites in Other Countries
Other sites in the Western Hemisphere have shown similar old dates to Chiquihuite Cave. These include Bluefish Caves in Canada and the Santa Elina shelter in Brazil. Tools similar to the transversal points found in Chiquihuite Cave have also been discovered at very old sites in South America. Some examples are the Toca da Tira Peia, Toca da Pena (Serra da Capivara National Park), and Toca da Janela da Barra do Antonião-Norte sites in Brazil.
See also
In Spanish: Cueva del Chiquihuite para niños
