On Oct. 13, 2000, Paul Sereno, a professor from the University of Chicago, guided a team of palaeontologists out of three broken Land Rovers, filled their water bottles and walked across the toffee-coloured Ténéré Desert. Ténéré, one of the most barren areas on Earth, is located on the southern flank of the Sahara. According to the turbaned Tuareg nomads, who have ruled this infertile domain for centuries, this California-sized ocean of sand and rock is a ‘desert within a desert’. In the Ténéré Desert, massive dunes might stretch a hundred miles, as far as the eye can see. In addition, 120-degree heat and inexorable winds can take almost all the water from a human body in less than a day.

Mike Hettwer, a photographer on the team, was attracted by the amazing scenery and walked to several dunes to take photos of the landscape. When he reached the first slope of a dune, he was shocked by the fact that the dunes were scattered with many bones. He photographed these bones with his digital camera and hurried back to the Land Rover. ‘I found some bones,’ Hettwer said to the other group members. ‘To my great surprise, they do not belong to dinosaurs. They are human bones.’

One day in the spring of 2005, Paul Sereno got in touch with Elena Garcea, a prestigious archaeologist at the University of Cassino in Italy, asking her to return to the site with him. After spending 30 years researching the history of the Nile in Sudan and the mountains in the Libyan Desert, Garcea was well acquainted with the life of ancient people in the Sahara. But she did not know Sereno before this exploration. His claim of having found so many skeletons in the Ténéré Desert seemed unreliable to some archaeologists, one of whom considered Sereno just a ‘moonlighting palaeontologist’. However, Garcea was sufficiently intrigued by his perspective to accept his invitation.

In the following three weeks, Sereno and Garcea, along with five excavators, five Tuareg guides and five soldiers from Niger’s army, sketched a detailed map of the site, which was dubbed Gobero after the Tuareg name for the area. After that, they excavated eight tombs and found twenty artefacts from the Kiffian and Tenerian civilisations. From these artefacts, it was evident that Kiffian fishermen caught not only small fish but also some huge ones: the remains of Nile perch, a fierce fish weighing about 300 pounds, along with those of alligators and hippos, were found near the dunes.

Sereno went back with some essential bones and artefacts and planned the next trip to the Sahara. Meanwhile, he carefully pulled out the teeth of skeletons and sent them to a research laboratory for radiocarbon dating. The results indicated that the smaller ‘sleeping’ skeletons might date back about 6,000 years, well within the Tenerian period, while the larger, tightly bundled burials were approximately 9,000 years old, just in the heyday of the Kiffian era. The scientists could now distinguish one culture from the other.

In the fall of 2006, the researchers returned to Gobero with a larger excavation team and six extra specialists. Garcea hoped to excavate about 80 more burials. At the site, Chris Stojanowski, a bioarchaeologist at Arizona State University, found clues in the bones. Judging from the bones, the Kiffian appeared to be peaceful and hardworking. ‘No injuries to heads or forearms indicate that they did not fight too much,’ he said. ‘And they had strong bodies.’ Pointing to a long, narrow femur, he continued, ‘From this muscle attachment, we could infer the huge leg muscles, which means this individual lived a strenuous lifestyle and ate much protein. Both of these inferences coincide with the lifestyle of people living by fishing.’ To create a striking contrast, he displayed the femur of a Tenerian male. Its ridge was scarcely visible, indicating a less laborious lifestyle, which might be expected of a herder.

Stojanowski concluded that the Tenerians were herders, which was consistent with other scholars’ dominant view of the lifestyle in the Sahara 6,000 years ago, when the dry climate favoured herding rather than hunting. But Sereno raised a confusing point: if the Tenerians were herders, where were the herds? Despite thousands of animal bones excavated in Gobero, only three cow skeletons were found, and none belonging to goats or sheep were found. ‘It is common for herding people not to kill cattle, particularly in a cemetery,’ Elena Garcea remarked. ‘Even modern pastoralists such as Niger’s Wodaabe are reluctant to slaughter animals in their herd.’ Sereno suggested, ‘Perhaps the Tenerians in Gobero were a transitional group that still relied greatly on hunting and fishing and had not adopted herding completely.’