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Homo ergaster was similar to Homo erectus and may have been an African subspecies of H. erectus or a distinct species; palaeontologists are not sure. H. ergaster lived less than two million years ago.
 Comparison with other homo types
H. ergaster had several features found in modern humans and may have been a direct ancestor. . The pelvis of H. ergaster was narrow as in modern humans and the rib cage had a modern human shape. The narrow pelvis caused problems for mothers giving birth. The brain of the new born evolved to be undeveloped so the head was small enough to pass through the narrow pelvis and the nuclear family may have come into being as mothers needed additional support caring for their undeveloped infants. One specimen of H. ergaster had ‘narrow cheek teeth’ and, ‘a smaller dental arcade’ suggesting that food was processed with stones and needed less chewing. The brain of H. ergaster was larger than that of typical H. erectus and tools found with H. ergaster were more advanced.