Early humans may have taken a detour into Eurasia before embarking on their epic journey out of Africa, according to new fossil evidence.
Palaeontologists in Georgia have unearthed remains of five primitive humans that date back to 1.8m years ago, suggesting some of our oldest ancestors lived in the region at the time.
The partial skeletons, which represent the earliest humans discovered outside Africa, challenge the theory that our ancestors evolved entirely on the continent and left the cradle of humanity only 60,000 years ago.
David Lordkipanidze, director of the Georgian National Museum, said the primitive humans were short, with small brains and strongly developed legs. Other remains suggest they lived alongside predators including sabre-toothed cats.
The fossils are thought to be early Homo erectus, a forerunner of modern humans, which lived in Africa 2m years ago. Lordkipanidze said some Homo erectus may have left Africa for Eurasia before returning much later.
The fossils were uncovered at the Dmanisi archaeological site south-west of the Georgian capital of Tbilisi. Remains thought to belong to two males and three females were found next to stone tools and animal bones bearing cut marks, suggesting the species prepared meat for food.
"The Dmanisi fossils are extremely important in showing us a very primitive stage in the evolution of Homo erectus," said Chris Stringer, head of human origins at the Natural History Museum in London. "They raise important questions about where that species originated."
By piecing the skeletal remains together, researchers estimate they stood about 1.5 metres tall and had brains a little more than half the size of those in modern humans.
Lordkipanidze said: "The Dmanisi people were almost modern in body proportions and were highly efficient walkers and runners. Their arms moved in a different way, and their brains were tiny compared to ours. They were sophisticated tool makers with high social and cognitive skills."
