Homo Erectus

Homo erectus (literally “upright man”) is an extinct hominin that lived between 1.8 million and50,000 years ago. The first fossil found of this species (the type specimen) was a skullcap discovered in 1891 by Eugène Dubois. However, the species was not named until 1894, after a femur (thigh bone) was discovered not far from the skullcap. The femur was nearly identical to that of a modern human, prompting Dubois to name a new species: Pithecanthropus erectus (literally “upright apeman”). Both fossils were found in Trinil,Java. The type specimen was named “Trinil 2” and the femur “Trinil 3.” They are more commonly known as “Java Man.”

In 1927, Davidson Black named a new species Sinanthropus erectus (literally “Northern upright man”), based on a tooth discovered at Zhoukoudian near Bejing (Peking), China. The later discovery of 14 calvaria (skull caps), limb bones, and many more teeth strengthened his claim. One of these calvaria became better known as “Peking Man.” As more fossils oferectus-like hominins were discovered, paleo-anthropologists began to recognize the similarities between Pithecanthropus/Sinanthropus and specimens that had been assigned to the genusHomo. Eventually, both Pithecanthropus and Sinanthropusfossils were subsumed into the species Homo erectus.

The morphology of Homo erectus changed very little over its 1.8 million years of existence. Compared with australopithecines and earlier Homo, Homo erectushad smaller teeth, a shorter face, and a humanlike projecting nose. The numerous skulls that have been discovered show a significant increase in brain size compared with earlier hominins. On average, the cranial capacity of Homo erectus was about 900 cc, although its range (750 cc–1,250 cc) overlaps that of modern humans (1,000 cc–2,000 cc).

Compared with modern humans, Homo erectuspossessed a robust and somewhat primitive-looking skull, face, and dentition. In general, the skull is long, and the forehead is low in profile. The face has marked brow ridges, and the back of the skull has a marked projection for attachment of strong neck muscles. The skull bones are thick compared with modern humans. Many of the Asian specimens (in particular) exhibit a sagittal keel, a ridge running along the top of the skull. All Homo erectus specimens lack the projecting chin of modern humans.

Their robusticity notwithstanding, below the neck Homo erectus looked very much like modern humans. Much of what we know about their postcranial skeleton (below the skull) comes from a nearly complete skeleton from Lake Turkana, known as “WT15000” or “Nariokotome Boy.” Nariokotome Boy would have been quite tall if he had reached adulthood (perhaps 180 cm, or6') but the average height of Homo erectuswas about 170 cm (5′7″). This size represents a dramatic increase in stature compared with earlier Homo.Postcranial remains establish that Homo erectuswas a committed biped with none of the adaptations to tree climbing observed in earlier hominins. It has been suggested that their somewhat narrower hips indicate that there were more efficient bipeds than the average modern human.

Compared with earlier hominins, Homo erectusexhibited greater control over its environment. This species developed a more sophisticated tool kit and may have mastered how to control fire. In addition, it was very likely the first hominin to move outside Africa. Homo erectus is known for developing Acheulean tools. These tools are found in high densities in Africa,Europe, and western/south Asia and are rare in East Asia. Like the Oldowan tools used by Homo habilis, Acheulean tools did not have specialized purposes. The Acheulean hand axe (a pear-shaped tool with sharp edges on all sides and a picklike point) was likely a kind of “Swiss Army knife” used to cut, scrape, pound, and dig. In addition to hand axes, the Acheulean tool kit included cleavers, scrapers, and notched tools. The greater diversity of tools likely indicates greater reliance on them.

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