A man walks on dunes on Oct. 26, 2016, near Morocco's southeastern oasis town of Erfoud, north of Er-Rissani in the Sahara Desert. New research has shed light on the desert's ancient climate.

(FADEL SENNA/AFP via Getty Images)

At a Glance

Researchers studied fossils found in a Sahara rock shelter dating back more than 10,000 years.They found fish bones that changed in volume, type and size over time.The fish bones indicated a period when the Sahara changed from savannah to desert.

The remains of fish eaten thousands of years ago by humans are shedding new light on ancient climate patterns in the Sahara Desert.

Researchers studying fossils found in a Sahara rock shelter dating back more than 10,000 years have uncovered fish bones that could serve as a record to the region's gradual shift from vibrant savannah to arid desert.

The findings were detailed in a published Thursday in the journal Plos One.

The research team found more than 17,500 animal remains in a rock shelter called Takarkori in the Acacus Mountains in southwest Libya, from a period ranging between 4,650 and 10,200 years ago. A vast majority of the remains were from fish, specifically tilapia and catfish.

Fewer fish bones were found from the later years of the period, indicating possible changes in the environment and climate.

"The amount of fish is decreasing through time and the contribution of mammals increases, showing that people at Takarkori focused gradually more on hunting and livestock keeping," the researchers wrote. "It is unclear if this was an intentional process or if this shift could be related to increasing aridity, which made the environment less favourable for fishes."

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In the oldest period, for example, fish bones made up about 90% of the remains, according to the study. As time went on, that percentage dropped to less than half. The size and types of tilapia and catfish also changed over time, switching to types that could better withstand things like higher temperatures and dryer conditions. The findings jibe with existing data that shows a shift from wet environments to more arid conditions.

Similar animal remains have been found in the Sahara before, but study co-author Wim van Neer from the Royal Belgian Institute of Natural Sciences told The Guardian because of the vast time period it covers.

“All the other finds are surface finds, [from] just one layer, one period, one event. Whereas what we have here is a 5,000-year sequence with a lot of bones – so that makes it special,” van Neer said.

Deserts are defined as , and the Sahara is the largest desert on Earth outside of the Arctic and Antarctic. It's also one of the hottest places on the planet. Other research in recent years has shown that due to warmer temperatures and less rain connected to climate change.

Experts say the new study on fish bones illustrates how climate can impact humans.

“There are not a whole lot of sites like Takarkori that show in the ways people were eating in this period of dramatic landscape change,” David Wright of the University of Oslo in Norway told New Scientist. “It is just one piece of the puzzle, but an important one as we wrestle with understanding how people can adapt to extreme forms of climate change.”

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