the range of Homo habilis: Homo erectus. The earliest "unambiguous" evidence is a whole cranium, KNM-ER 3733 (a find identifier) from Koobi Fora in Kenya, dated to 1.78 mya. An early skull fragment, KNM-ER 2598, dated to 1.9 mya, is considered a good candidate also. Transitions in paleoanthropology are always hard to find, if not impossible, but based on the "long-legged" limb morphology shared by H. habilis and H. rudolfensis in East Africa, an evolution from one of those two has been suggested. The most immediate cause of the new adjustments appears to have been an increasing aridity in the region and consequent contraction of parkland savanna, interspersed with trees and groves, in favor of open grassland, dated 1.8–1.7 mya. During that transitional period the percentage of grazers among the fossil species increased from around 15–25% to 45%, dispersing the food supply and requiring a facility among the hunters to travel longer distances comfortably, which H. erectus obviously had. The ultimate proof is the "dispersal" of H. erectus "across much of Africa and Asia, substantially before the development of the Mode 2 technology and use of fire ...." H. erectus carried Mode 1 tools over Eurasia. According to the current evidence (which may change at any time) Mode 1 tools are documented from about 2.6 mya to about 1.5 mya in Africa, and to 0.5 mya outside of it. The genus Homo is known from H. habilis and H. rudolfensis from 2.3 to 2.0 mya, with the latest habilis being an upper jaw from Koobi Fora, Kenya, from 1.4 mya. H. erectus is dated 1.8–0.6 mya. According to this chronology Mode 1 was inherited by Homo from unknown Hominans, probably Australopithecus and Paranthropus, who must have continued on with Mode 1 and then with Mode 2 until their extinction no later than 1.1 mya. Meanwhile, living contemporaneously in the same regions H. habilis inherited the tools around 2.3 mya. At about 1.9 mya H. erectus came on stage and lived contemporaneously with the others. Mode 1 was now being shared by a number of Hominans over the same ranges, presumably subsisting in different niches, but the archaeology is not precise enough to say which. Oldowan out of Africa Tools of the Oldowan tradition first came to archaeological attention in Europe, where, being intrusive and not well defined, compared to the Acheulean, they were puzzling to archaeologists. The mystery would be