Before the Sahara desert ended as a desert region 12,000 years ago, the environment in southwestern Libya was a landscape in which water and life flowed. This is the conclusion of a team of paleontologists who have discovered 17,551 identifiable remains in the Tadrart Acacus Mountains . Of all those animals, 80% were the remains of fish – such as tilapia and catfish – that fed the first humans during the Holocene period.
The remains, which experts say cut marks and burn marks on the bones reveal that the fish were eaten by humans who used that shelter, date to between 10,200 and 4,650 years ago , and span much of the early Middle Period. and the Holocene, the current geological epoch. The rest of the remains consisted of mammals (about 19%) and a small amount of remains of birds, reptiles, mollusks, and amphibians.
It is not the first time that fish remains have been found in what are now dry and arid regions of the desert, but the team says it is the first time that ancient climate has been traced through animal remains.
“The other discoveries are surface finds, of just one layer, one period, one event. While what we have here is a 5,000-year sequence with many bones, that makes it special, “explained Wim van Neer from the Royal Belgian Institute of Natural Sciences, co-author of the study, which has been published in the open access journal PLOS ONE. .
Multiple human settlements and diverse fauna
The rock shelters within the Tadrart Acacus preserve not only important floral and fauna remains, but also important cultural artifacts and rock art due to the early occupation of these shelters during the Holocene. The experts identified and dated the animal remains found at this site and investigated changes in the abundance and type of these animal remains over time.
They also found that tilapia declined significantly over time, which may be because catfish have the ability to breathe air out of the water and survive longer in warm, shallow water.
The researchers believe that this disappearance of fish occurred as the number of mammals increased, suggesting that humans living in the mountains relied on hunting for survival.
“This study reveals the ancient hydrographic network of the Sahara and its interconnection with the Nile, providing crucial information on the dramatic climate changes that led to the formation of the largest desert in the world,” the authors clarify.
“The rock refuge of Takarkori has once again proven to be a true treasure for African archeology and beyond: a fundamental place to reconstruct the complex dynamics between ancient human groups and their environment in a changing climate,” they conclude.
The findings coincide with previous evidence from the Sahara, including sediments and geological features, which led to a change in climate from a more humid environment with vegetation and abundant lakes more than 10,000 years ago, to a period of fluctuating dry conditions. and humid, until about 5,500 years ago. The region became increasingly arid, resulting in the landscape that we can see today.
Referencia: Van Neer W, Alhaique F, Wouters W, Dierickx K, Gala M, Goffette Q, et al. (2020) Aquatic fauna from the Takarkori rock shelter reveals the Holocene central Saharan climate and palaeohydrography. PLoS ONE 15(2): e0228588. doi.org/10.1371/journal.pone.0228588
