Olduvai, Omo, East Turkana (all in Kenya); perhaps Swartkrans (South Africa); Hadar (Ethiopia).
2.4 to 1.6 mya.
Body size and dimorphism uncertain, but possibly 40-50 kg.
Around 650 cc (700+ cc or more in robust specimens, 500-600 cc in gracile specimens).
Large thick-boned face (smaller in gracile forms), rounded brain case. Large incisors and canines. Larger habilis specimens have molars and premolars larger than ours, whereas ergaster specimens have molars and premolars more similar to ours. (However, even the larger habilis specimens have smaller molars and premolars than those of most australopithecines.) gracile specimens have smaller brains, smaller faces, and smaller molars and premolars.
The bulge of Broca's area in the brain, essential for speech in modern humans, is believed to be visible in one endocast, suggesting to some scholars that H. habilis may possibly have had some form of speech. If so, we would expect a similar capacity in later, descendant forms, especially H. ergaster and H. erectus, for which we lack evidence so far.
More similar to those of Australopithecus than to those of later Homo. H. habilis had very short stature (similar to that of the famous Au. afarensis “Lucy”), with arm length almost equal to leg length. However some researchers suggest that even slightly longer leg length is compatible with bipedalism., not surprising since antecedent Australopithecus forms were apparently bipedal.
Some researchers believe the great variation in size within the species simply represents sexual dimorphism, with the gracile specimens being females and the robust specimens being males. If so, this species was far more dimorphic than any hominoid species living today. Other specialists suspect that there may actually be two species. (In that case, the more robust form is called Homo rudolfensis.)
Believed to be the maker of the earliest known stone tools (Oldowan tools). Generally believed to be a scavenger, not a hunter. (More About Oldowan Tools)