A new study shows the physical, genetic and cultural adaptation that our ancestors had to go through to overcome this difficult period
During the last ice age around 45,000 years ago, humans living in what is now Ethiopia settled in mountains 4,000 meters above sea level and survived by eating huge rodents.
The inhabitants of Ethiopia did not remain in the lowlands during the last Ice Age , but instead settled in the inhospitable region of the Bale Mountains .
There they had water , built tools with obsidian (a rock of volcanic origin) and fed on giant rodents.
The Bale Mountains are located about 280 kilometers northwest of Addis Ababa and near Lake Chomen, where the level of oxygen in the air is low, temperatures vary widely and it rains heavily.
During the most recent Ice Age the settlement was located beyond the edge of the glaciers.
“Because of these adverse conditions until now it has been assumed that humans settled in the mountainous region much later and for short periods of time,” explained lead author Bruno Glaser, an expert in soil biogeochemistry at Martin Luther University. from Halle-Wittenberg.
The study, in which the German universities of Cologne, Marburg and Rostock (Germany), as well as those of Bern (Switzerland) and Addis Ababa, also collaborated, provides new insights into the history of human settlements in Africa.
It also provides important information about the potential of humans to adapt physically, genetically, and culturally to changing environmental conditions.
An example of this is the ability of some groups that currently live in the Ethiopian mountains to deal with the low levels of oxygen in the air without difficulty .
The international team of researchers included archaeologists, soil experts, paleoecologists and biologists who found evidence of long-term human habitation on Bale’s ice-free plains during the Middle Pleistocene, when the valleys were too dry to survive.
For years, researchers have studied a rocky outcrop near the Fincha Habera settlement in the Bale Mountains of southern Ethiopia, where they have found various stone artifacts, clay fragments and glass beads .
“We also extracted information from the soil as part of our subproject,” Glaser said.
Based on the sediment deposits, the scientists did biomarker and nutrient analysis and carried out carbon dating processes, which allowed them to determine how many inhabitants the region had and where exactly they lived.
For this work, the scientists developed a new type of paleothermometer with which they could measure the climate in the area, including temperature, humidity and rainfall.
This analysis can only be done in natural areas with little contamination, where the soil has not changed much. The conditions in the Bale Mountains are ideal for this, as changes to the ground have been superficial in the last millennium.
Scientists were even able to determine what was the basis of the diet of these humans: huge underground-dwelling rodents, endemic to the region and easy to hunt.
The area also contains deposits of obsidian, volcanic rocks that early humans used to make weapons and tools .