Fossils tell tale of wetter Sahara

The Takarkori rock shelter in southwestern Libya is a time capsule, providing clues to the desert environment between five and ten thousand years ago, says lead author, Wim Van Neer, from the Royal Belgian Institute of Natural Sciences in Belgium.   

Working with the Libyan Department of Antiquities, Van Neer and colleagues from Italy analyzed thousands of fossilized animal bones, particularly those of fish, crocodiles and turtles, as well as rock shelter sediments and satellite images. 

Cut marks on the bones and carbon traces of burning show all of the fish and most of the other remains, including mammals, were human food refuse. Stone structures, fireplaces, and burials of women and children indicate that hunter-gatherers and nomadic herders camped at the shelter briefly at different times. 

The researchers found that the amount of fish decreased over time: from 90 percent of all remains between 10,200 and 8,000 years ago to only 40 percent of all remains around 4,500 years ago. This shift, they say, could be related to increasing aridity, which reduced the water bodies, making the environment less favourable for fish. 

The predominant fish were tilapia and catfish. The number and size of tilapia decreased over time, while catfish thrived due to their ability to survive in shallow, high temperature waters.  

While the overall fish population dwindled, mammal numbers increased, suggesting that the occupants of Takarkori focused more on rearing livestock when the desert became drier.

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