"H. rudolfensis" is not associated with any tools. However, the greater molar cusp relief in "H. rudolfensis" and "H. habilis" compared to "Australopithecus" suggests the former two used tools to fracture tough foods (such as pliable plant parts or meat), otherwise the cusps would have been more worn down. Nonetheless, the jaw adaptations for processing mechanically challenging food indicates technological advancement did not greatly affect their diet. Large concentrations of stone tools are known from Koobi Fora. Because these aggregations are coincident with the emergence of "H. ergaster", it is probable "H. ergaster" manufactured them, though it is not possible to definitively attribute the tools to a species because "H. rudolfensis", "H. habilis", and "P. boisei" are also well-known from the area. The oldest specimen of "Homo", LD 350-1, is associated with the Oldowan stone tool industry, meaning this tradition had been in use by the genus since near its emergence.