Homo erectus was probably the first human to live in a hunter-gatherer society, and anthropologists such asRichard Leakey believe that it was socially more like modern humans than the more Australopithecus-like species beforeit. Likewise, increased cranial capacity generally coincides with the more sophisticated tools occasionally found withfossils. The first theory is that H. erectus migrated from Africa during the Early Pleistocene, possibly as a result of the operation of the Saharan pump, around 2.0 million years ago, and dispersed throughout much of the Old World. Fossilized remains 1.8 to 1 million years old have been found in Africa (e.g., Lake Turkana and Olduvai Gorge), Europe (Georgia, Spain), Indonesia (e.g., Sangiran and Trinil), Vietnam, China (e.g., Shaanxi) and India. The second theory is H. erectus evolved in Asia and then migrated to Africa. The species occupied a West Asian site called Dmanisi, in Georgia, from 1.85 million to 1.77 million years ago, at the same time or slightly before the earliest evidence in Africa. Excavations found 73 stone tools for cutting and chopping and 34 bone fragments from unidentified creatures.