It's not just a theory; a scientific team from the University of Barcelona and the University of Alcalá has been able to prove it by tracing the trail of cut stone tools recovered from the Peña Capón site (Muriel/Tamajón, Guadalajara): 25,000 years ago, the hunter-gatherers of the Peña Capón area. The researchers followed the trail of flint tools that different groups of hunter-gatherers exchanged over the years and found evidence that the stones traveled a distance of about 700 kilometers. They originated in the area where Saint-Sulpice-de-Excideuil and Mauprévoir are located today, in the Dordogne department of southwestern France, and ended up at Peña Capón, in the center of the Iberian Peninsula. The authors of the study argue that the social networks reached an area of ​​nearly 89,000 square kilometers. The tools would have been exchanged between interconnected groups. "One of these pieces traveled inside a leather bag and was not used for hunting or cutting. That's why we believe it had symbolic value," says Marta Sánchez de la Torre, professor at the University of Barcelona and co-author of the article published in the journal Science AdvancesThe tools would have been used to strengthen social alliances and maintain contact between different groups during the Last Glacial Maximum, when conditions were very harsh due to extreme cold and food scarcity. "We have also been able to verify, at other sites such as Montlleó, in the municipality of Prats i Sansor, in the Cerdanya region, that the colder it was and the worse the conditions, the greater the interconnection and exchange," says Sánchez. "There was not only an exchange of tools, but also of people, and that was key to the survival of these groups, which were quite small, usually consisting of 20 or 30 people," he adds.