A pair of archaeologists have uncovered a strange series of rock art carvings that show boats and cattle – both vitally in need of water to work properly – in the middle of one of the driest parts of the African desert.
It’s a finding that sheds light on the changing face of North Africa’s ancient environment and a climate collapse around 5,000 years ago.
In archaeology, Nubia – an ancient region of modern-day Sudan – is the lesser-known cousin of the storied history of its northern neighbour Egypt.
Julien Cooper is an archaeologist from Macquarie University. Through previous appointments at Yale and Oxford, he began his career working in Egypt but has been most recently able to move south along the Nile to study Nubian sites.
It’s here that a surprise discovery had been made by his colleagues, including co-author Dorian Vanhulle from the Institute of Mediterranean and Oriental Culture at the Polish Academy of Science.
The pair have published findings in The Journal of Egyptian Archaeology that illuminate rare rock art from the Atbai Desert east of Wadi Halfa (وادي حلفا), a town on the banks of the Nile River.
The art, which is more than 5,000 years old, depicts a series of illustrations, particularly cattle and ships.
“There’s lots of unanswered questions about the history of Sudan,” Cooper tells Cosmos. “There’s a fascinating interface between the cultures of say, the Middle East and Mediterranean and the cultures of Africa, and this is exactly what we see – in Sudan, we see lots of things coming from the north in Egypt, the Roman Empire, the empires of Alexander the Great.”
There’s no surprise that Nubian rock art features boats, which Cooper points out are a well-known facet of life in the 4,000-3,000BCE period this culture existed.
It’s unsurprising that cattle appeared, given the pasture-based communities known to have lived along the Nile.
But what is surprising is that representations of these two cultural staples were found more than 100km inland from Wadi Halfa, among the golden sands of Sudan’s eastern deserts which average 0mm of rain each year.
“When you find these boats way out in the desert, then you have lots of follow-on questions,” Cooper says.
“At this early prehistoric period, we have almost no evidence of Egyptians or Nubians going this far into the desert and that’s why it was really unexpected to find this large scene of boats.”
Cooper also describes the art as “nicely carved” as opposed to what is usually seen with desert rock art. It suggests inhabitants of the rock shelters where the art was found had made themselves at home for some time.
While Cooper and Vanhulle can’t explain the reason for the style or existence of the rock art in this location, they do theorise why so much rock art is found in such an arid, little-populated part of the desert, which would be incapable of supporting livestock.
“Usually, we’re looking at something upwards of 200-300mm of rainfall for a healthy cattle herd,” he says. “Which tells us that the climate here used to be much better for livestock herding and nomadism.”
The disappearance of a so-called ‘Green Sahara’ has been established by archaeological missions as having started around 3,000BCE – just after the engravings were made on the inland rock shelters described by Cooper and Vanhulle.
“And what we know happened is it was a collapse in the African monsoon. So there’s the tropical belt of Africa, which has this monsoon in summer and before 3,000BCE, it extended much further north, almost into Egypt,” Cooper says.
Sudan’s capital Khartoum is about 700km south of Wadi Halfa, where the White and Blue Niles join, and is roughly the upper limit of Africa’s arable land.
The desert that separates the two cities today is a far cry from what would have been similar to savannah grasslands commonly found throughout sub-Saharan Africa 5,000 years ago and emphasises the substantial climate change that unfurled after the rock walls were engraved.
The Neolithic Revolution in Nubia-Sudan
“I think this is like one of these really sort of fortuitous moments in world history,” says Cooper.
Before the climate collapse agricultural practices allowed people to begin congregating in cities.
With high rainfall in the Green Sahara, Nubian cultures would have been able to establish themselves further inland than the banks of the Nile allow today.
“But it’s lucky that when all these things arrived in North Africa, it was a time where the rainfall was conducive,” says Cooper. “If the Neolithic arrived later, it would have been very difficult or impossible to keep cattle, except outside the banks of the Nile River.
“And then you have problems of livestock and farming on the one river system and in competing for the same pasture which is what we know happened in later periods where you do have sort of a distinction between nomads and livestock in the desert and then people on the riverbank who are growing crops.”
Come the collapse of the monsoonal climate systems north of Khartoum, groups would have been forced to move back towards the river and further south to keep agricultural practices alive.
Cooper says such a moment fits with the rise of the ancient Egyptian and Nubian states around 3,000BCE.
“And we don’t think this is an accident. We think that something related to this climate shift and migration caused a demographic and migratory upheaval that would eventuate in the beginnings of the Egyptian state.”
