Just as 100,000 years ago, modern humans in southern Africa started to settle down. Just why and how this momentous shift in our remote ancestors’ way of life occurred is hard for scholars to say.
Prehistoric hunter-gatherers from this era are one of the most challenging humans to study. They did not leave behind any permanent structures as proof of the presence, and their stone tools are seldom found together with contextual information such as the remains of plants or bones. Other artifacts, including beads or ochre paint, are extremely rare, and materials like leather and wood don’t survive. But one available resource is proof of the food they ate. Changes in their diet may have had deep consequences in thetransition from residing in highly mobile groups of hunter gatherers to more sedentary communities.
One of the several locations and surroundings in Africa where archaeologists are currently studying hunter gatherers, coastal South Africa has some of the earliest signs of coordinated social behaviors. Loftus clarifies that seashells are especially informative because they grow in regular seasonal and annual increments, like trees, and survive well in the archaeological record. By measuring a shell’s oxygenisotope ratios, researchers can receive a record of every growth period in its history, as well as rainfall levels and atmosphere and sea-surface temperatures.As long because there is not any recrystallization or dis-solution at which the carbonate structure of this shell partly dissolves, inducing irreversibe harm, Loftus believes that researchers could likely recover this data dating back up to millions of years back. Studying a shell’s growth phases also allows archaeologists to determine the season in which it was chosen. “We can monitor where people were on the landscape at various times throughout the year,”Loftus says,”and this can shed light on the amount of group freedom, an important component of how historical societies organized themselves.”
Archaeologist Curtis Marean of the Institute of Human Origins at Arizona State University believes that putting the function of coastal living in the big picture of human development and identifying the shift to”dense and predictable”food resources such as shellfish are critical to understanding early modern people’ social development. Marean also studies websites on the coast of South Africa and has found that their bountiful food resources supported territoriality and that social organization was needed to shield the newly established territory. The high nutritional value of shellfish may alsohave helped boost Homo sapiens’ cognitive capacity. “When hunterrgatherers enlarged their diet to include coastal resources, they ended up having characteristics unique among hunter gatherers,”says Marean. “They did not move across the landscape considerably, and their inhabitants increased, as did the sophistication of the tool kit. “Such social development isn’t known to have occurred this early anyplace.
Marean further hypothesizes that this sort of social development resulted in Homo sapiens’ possibly most significant,and many peculiar, quality-cooperation. “Cooperation is a very bizarre trait,”says Marean. “The high levels of collaboration with non-kin that contemporary humans express is entirely unique in the animal kingdom. “Eventually, collaboration fostered group migration and led to Homo sapien’domination of the planet. Marean and others working on the Southern African coast have recognized shards of volcanic glass in the cataclysmic eruption of Mt.Toba on Sumatra 74,000 years ago, which many scholars think may have come closeto wiping out humanity. Marean considers that common coastal food resources from South Africa helped several hundred Homo sapiens escape annihilation, and that these fortunate survivors could have become thecommon ancestors of today’s 7.8 billion modern humans.