Anatomically Modern Humans

Anatomically modern H. sapiens first arose in Africa and then eventually spread to nearly every corner of the earth, capable of surviving in all climates and environments. The second major dispersal ofhominins, undertaken by modern humans, was a wider dispersal than that of the initial dispersal by H. erectus. Modern humans appear in Europe around 40 Kya, in Australia between 60 and 50 Kya, made it across the Bering Strait from Russia to North America some time around 30 Kya, and almost immediately appear in South America after that (Figure 6.1).

Several skeletons found at the Cro-Magnon rock shelter site at Les Eyzies in France, date to around 40 Kya. It is because of this notable discovery by Louis Lartet in 1868 that we adopted the nickname "Cro-Magnons" for fossils of our species.

Until recently the oldest modern human fossils came from the Herto site in the Afar Region of Ethiopia, dating to about 160 Kya. The three individuals, including two skulls, still retain small browridges and other primitive features so the discoverers gave them a subspecies Homo sapiens idaltu meaning "elder." One of the skulls had cut marks and was polished probably from being carried around after the individual died, perhaps indicating an early stage of ritual behavior.

Now that the site has been redated to 195 Kya, the very earliest fossils of fully modern humans on record are two skeletons, Omo I and II, which were found near Ethiopia's Omo River, right across from the northern border of Kenya. These fossils confirm molecular clock estimates which point to an East African origin for our species at around 200 Kya (see Chapter 4).

Although there is variation among and within modern populations, all humans share cranial features that distinguish us from earlier ho-minins. These traits include high round skulls, vertical flat foreheads with small or no browridges, chins, and an average brain size of 1,350 cc—slightly smaller on average per body size than Neanderthals, but larger than any other hominins. There is little to no postorbital constriction meaning the muscles for chewing are extremely reduced and the brain is expanded in their place. The small jaw has a prominent chin and small teeth. The muscle markings on the skull and the entire skeleton are less robust and the bones are more gracile or slender and weak than previous hominins. The face is tucked under the skull and is less prognathic than in previous hominins. The earliest humans also had tropical body proportions (see Chapter 5).

Once modern humans emerged they filled tropical, temperate, and arctic niches almost immediately. The first humans were foragers, gatherers, hunters of large and small prey, and fishermen. They traveled far distances to obtain raw materials or to trade for them. Their behavior and culture is characterized by complexity, flexibility, and innovation. For the first time, bones were being made into needles (oldest are 26 Kya), awls for sewing clothing, and spear-throwers (or "atlatls"), which add incredible velocity and distance to a thrown spear. Beads, pendants, and other evidence ofpersonal adornment are everywhere by the time modern humans take over in the Upper Paleolithic or Late Stone Age.

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