4,000-year-old rock paintings discovered in Sudan confirm that the Sahara looked very different not so long ago

In one of the driest parts of the Saraha Desert, scientists have made a remarkable discovery. In a cave they discovered petroglyphs of cattle. It confirms what researchers have known for some time, namely that the dry and virtually deserted Sahara must have been green, lush and inhabited several thousand years ago.

Archaeologists discovered the petroglyphs near the modern city of Wadi Halfa, in Sudan. Today the area has a warm desert climate; the sun shines extremely brightly for an average of 4,300 hours per year and rain can sometimes take years to arrive. But that was different in the past, as rock carvings that have now been discovered in sixteen different places in the area confirm.

Puzzling
Almost all petroglyphs show cattle. “It was puzzling to see cattle depicted in the rocky walls in the desert,” says researcher Julien Cooper. “Since cattle require a lot of water and hectares of pasture and would not survive in the arid environment that the Sahara is today.”

Green Sahara
However, dating of the petroglyphs quickly showed that they are about 4,000 years old. And with that, the puzzle pieces finally fell into place. Because previous research has already shown that there was a ‘green Sahara’ several thousand years ago. The area at that time – also referred to as the ‘African Humid Period’ – would have been much moister and greener than today. And the rock paintings now found in Sudan confirm that. “The presence of cattle in ancient rock art is one of the most important pieces of evidence that the Sahara was once green,” Cooper said.

African humid period
The African Humid Period began about 15,000 years ago. The North African monsoon increased in strength – probably due to variations in the Earth’s orbit – and as a result much more precipitation fell in the Sahara. This caused the vegetation – in the form of grass, shrubs and trees – to increase, turning the desert green. About 5,000 years ago, the African humid period came to an end and the desert climate as we know it now slowly regained the upper hand.

Lakes and rivers
The discovered drawings not only show cattle; the researchers also spotted grasslands with lakes, rivers, swamps and wells. People are sometimes depicted next to the cattle, which may indicate that they milked the cattle. It would mean that this area was used by so-called pastoralists: livestock farmers who let their domesticated animals graze on natural grasslands or meadows, the researchers write in The Journal of Egyptian Archaeology. The researchers think that these pastoralists could have survived reasonably well in this area until about 3,000 or at most 2,000 years ago. After that the area became too dry to keep cattle.

Cover
It therefore has everything to do with a drastic climate change that started in the Sahara several thousand years ago and put an end to the African humid period. Lakes and rivers began to dry up. Sand covered the parched, brown grasslands and most people left the once green Sahara and settled closer to the Nile. “The Atbai Desert around Wadi Halfa, where the new rock art was discovered, has been almost completely abandoned by humans,” says Cooper. “And those who did stay stopped raising cattle and switched to sheep and goats.”

When you see the petroglyphs that literally paint a picture of life during the African Humid Period, it becomes clear that the end of that period must have had an enormous impact on the people who lived in the previously green Sahara. “It must have had enormous consequences for virtually all aspects of human life,” Cooper confirms. For example, the diet of the people – who previously always kept and milked cattle – must have changed. Just like the migration routes along which shepherds led their cattle for thousands of years in a row. But the climate change also had consequences, for example, “for the identity and livelihoods of those who depended on their livestock,” Cooper thinks.