5.3 The Emergence of Us: The Archaic Homo

Homo antecessor

Homo antecessor has been found in Spain, France, and England and dates to around 1.2 MYA to 800 KYA. These specimens represent the oldest fossil evidence for the presence of the genus Homo in Europe. Some scientists have suggested that this species is the ancestor of Homo heidelbergensis, while others suggest that H. antecessor is the descendent of H. ergaster. Homo antecessor was first found at the Sima de los Huesos site of the Sierra de Atapuerca region in Spain. Within this site is a cave known as the Pit of Bones, where more than 1,600 fossils of 28 individuals have been found that date at or before 780,000 years ago. The site is an important one that stretches over a long period of time and displays the emergence and divergence of various Homo physical characteristics that later appear in the Neanderthal. Evidence from nuclear DNA suggests that early hominins at this site were related to the Neanderthal and not the Denisovans, indicating divergence earlier than 430,000 years ago (Meyer et al. 2016). The section on the Neanderthal will explore further the interbreeding and divergences of the Neanderthal, Denisovans, and modern Homo sapiens.

Homo antecessor was almost six feet tall and males weighed about 200 pounds, well within the range of variation for modern humans. Other anatomical features of this species include a protruding occipital bun (a bulge found in the occipital area of the skull), a low forehead, no strong chin, and a cranial capacity of about 1,000 cc. It has been suggested that the purpose of the occipital bun is to balance the weight of the anterior portion of the skull and face. One very modern trait exhibited by this species is the presence of a facial depression above the canine tooth called the canine fossa, which is also found in modern humans. The best-preserved fossil is a maxilla (upper jawbone) of a 10-year-old individual.

In addition to the fossil bones, 200 stone tools and 300 animal bones were also found at Gran Dolina, another location at the Atapuerca site, along with a carved stone knife. Stone tools at this site were predominantly Oldowan style and constructed from local raw materials. Tools included cutting flakes and hand-held cores. It has been suggested that the absence of retouched tools at this site indicates that these tools were created primarily for processing and eating meat. Cutmarks are present on the majority of animal remains. One of the most intriguing observations about this site is that there are numerous large animal carcasses (mostly deer) that are believed to have been transported to the site rather than consumed where they were killed. Some scientists have suggested that the practice of bringing food back to the site is evidence of social cooperation, suggesting both a division of labor and a custom of food sharing.

Many of the bones of Homo antecessor show the same evidence of cutmarks as the animal bones, indicating that flesh was removed from the bones with the goal of dismemberment. Some scientists have taken this to mean that H. antecessor practiced cannibalism. However, humans have also been known to remove the flesh from bones during funerary rites. Whether the cutmarks made by H. antecessor represent cannibalism, a funerary rite, or another yet unknown practice is still being debated.

Homo heidelbergensis

Homo heidelbergensis is an incredibly variable group. Many archaic Homo species are included in this group because they possess features that can best be described as a mosaic between H. ergaster, H. erectus, and anatomically modern humans (AMH). This section looks at just a few of the specimens that are regularly attributed to Homo heidelbergensis.

One of the most important Homo heidelbergensis specimens is known as Mauer. It was found in 1907 in Germany and is represented by a mandible (lower jaw) that is dated to approximately 600,000 years ago. It has a robust mandible and a receding chin like earlier Homo ergaster but has very small molars like anatomically modern H. sapiens. The jaw is so big and the teeth are so small that there is plenty of space for additional teeth to develop behind the wisdom teeth. Given that the third molar (the wisdom tooth) has already erupted, it has been suggested that this individual was between 20 and 30 years at death.

Figure 5.12 This jawbone from a Homo heidelbergensis specimen was found in Germany in 1907 and is dated to approximately 600,000 years ago. (credit: Gerbil/Wikimedia Commons, CC BY 3.0)

Another important specimen of Homo heidelbergensis is known as the Petralona cranium. It was found in 1960 in Greece. Dates are uncertain but believed to be in the range of 100,000 to 700,000 years. Animal fossils found with the specimen indicate Petralona is between 350,000 and 200,000 years old. It combines Homo ergaster–like traits, such as massive brow ridges and thick cranial bones, with a cranial capacity of 1,200 cc, which is similar to anatomically modern H. sapiens.

A third specimen of Homo heidelbergensis is known as Bodo. It is very possibly the oldest archaic human specimen from Africa and was found in Ethiopia in 1976. It is dated to approximately 600,000 years and has a relatively large cranial capacity of 1,250 cc, which is again within the range of variation for modern humans. It is a robust cranium with very thick bones and two separate brow ridges.

Homo heidelbergensis Technology and Culture

Bodo is associated with Acheulean bifacial hand axes. Some scientists have suggested that Bodo butchered animals because Acheulean hand axes have been found with animal bones. There are cutmarks on the Bodo cranium that resemble those made by cutting fresh bone with stone tools. It has been suggested that the Bodo cranium is the earliest evidence of the removal of flesh immediately after death using a stone tool. The cutmarks were made symmetrically and with specific patterns on the cranium, which is interpreted as strong evidence that the defleshing was done purposefully for funerary practices. Once again, others have suggested that the cutmarks indicate that Bodo may have been practicing cannibalism.

In addition to their use of stone tools from the Acheulean tool industry, Homo heidelbergensis is also believed to have used spears. The earliest known spears have been found in Schöningen, Germany, and are dated to about 400,000 years ago. The spears were made either from spruce or pine wood and are believed to have had a range of about 35 meters. Probably the most important technological achievement evident in these spears is the use of hafting technology. Hafting involves attaching stone points to a handle made of another substance, such as wood, metal, or bone. The spears found at Schöningen represent one of the first known instances in which hominins united separate elements into a single tool.

Hafting gives stone tools more utility, as they can now be thrown (as with a spear), shot (as with an arrow), or used with more leverage (like an axe). These hafted stone points are able to be used with increased force and effectiveness, allowing people to hunt and kill animals more efficiently. This increased efficiency in hunting and killing animals is believed to have created a situation in which H. heidelbergensis had regular access to meat and other high-quality foods. Some have suggested that the presence of spears represent evidence that H. heidelbergensis could hunt herd animals that can run faster than a human, and that they had sophisticated hunting strategies requiring cognitive skills like anticipatory planning.

Like Homo ergaster and Homo erectus, Homo heidelbergensis occupied both caves and open-air sites. However, they did not just use the sites as is, they modified them. One of the most interesting aspects of the cultural behavior of Homo heidelbergensis is that they are associated with clear archeological evidence for modified dwellings. For example, in the Czech Republic there is a modified dwelling that consists of a stone foundation that is approximately 700,000 years old. Most likely, this dwelling had a roof constructed of thick branches. Other modified dwellings have been found in Germany and France.

Evidence of controlled fire has been found at most reasonably preserved Homo heidelbergensis sites. The oldest established continuous fire site for Homo heidelbergensis is from Israel and is dated to around 780,000 years old.

Figure 5.13 Phylogenetic tree and proposed migration routes of genus Homo heidelbergensis and later Denisovans and Neanderthals. (attribution: Copyright Rice University, OpenStax, under CC BY 4.0 license)

Homo naledi: A Rising Star

The most recently described archaic Homo is known as Homo naledi. They were found in the Rising Star cave system in South Africa in 2013 and 2014 (Figures 5.14–5.15) and are dated to approximately 235,000–335,000 years old. Over 1,500 bones from as many as 15 individuals were recovered from the cave, which is possibly the largest assemblage of a single hominin species yet discovered. Despite their relatively recent date, they have exceptionally small cranial capacities, comparable to the robust and gracile australopithecines, which are around 560 cc. The encephalization quotient of H. naledi is estimated at 4.5, which is the same as H. floresiensis but notably smaller than all other Homo (contemporary Homo are all above 6). The presence of this small-brained hominin at the same time that Neanderthals and Homo heidelbergensis were around is further evidence that multiple hominin lineages were coexisting and evolving at the same time. The classification of H. naledi proved to be a challenge, as the specimens presented a mosaic of traits and characteristics associated with an array of other hominin species.

Figure 5.14 Maps showing the location of the Cradle of Humankind World Heritage Site in South Africa, where Homo naledi fossils were found in the Rising Star cave system. (credit: Hawks et al. (2017), eLife, CC BY 4.0)

Figure 5.15 The Rising Star cave system, showing geological features and the location of the excavation area where numerous Homo naledi specimens have been found. (credit: Paul H. G. M. Dirks et al. (2015), eLife/Wikimedia Commons, CC BY 4.0)

Figure 5.16 H. naledi skulls. It is apparent in these images that this species had rather pronounced prognathism (Credit: John Hawks, Marina Elliott, Peter Schmid et al. (2017), eLife/Wikimedia Commons, CC BY 4.0)

Figure 5.17 H. naledi feet were much like those of modern humans. (credit: W. E. H. Harcourt-Smith, Z. Throckmorton, K. A. Congdon, B. Zipfel, A. S. Deane, M. S. M. Drapeau, S. E. Churchill, L. R. Berger & J. M. DeSilva (2015)/Nature Communications/Wikimedia Commons, CC BY 4.0)

Figure 5.18 The hands of H. naledi display curved finger bones and large thumbs, indicating that it still had an adaptation for climbing trees. (credit: Lee R. Berger et al. (2015), eLife/Wikimedia Commons, CC BY 4.0)

Figure 5.19 Comparison of some of the most commonly known Homo species (credit: Chris Stringer, Natural History Museum, United Kingdom (2015), eLife/Wikimedia Commons, CC BY 4.0)

Homo naledi: Did They Bury Their Dead?

Homo naledi has not yet been found in association with any stone tools. Despite a lack of established tool use, there is fairly convincing evidence that H. naledi may have used the cave system as a place to bury their dead. The hypothesis that H. naledi had a ritualistic mortuary practice is based on several observations, such as the bones appearing to lack evidence of gnawing marks from predators and the lack of evidence of layers of sediment that would suggest the bones were deposited by flooding (Dirks et al. 2015). In 2017 additional fossil remains were found in a second chamber in the Rising Star cave system (Hawks et al. 2017), but these remains don’t as yet appear to offer additional evidence to support the hypothesis of an intentional burial.

Some scientists believe that there is insufficient evidence to conclude that H. naledi were involved in funerary ritual practices. They have noted that the preservation of H. naledi specimens are similar to that of cave-dwelling baboons that have died natural deaths. At Sima de los Huesos, remains of about 28 Neanderthal and H. heidelbergensis fossils were found in a cave dated to about 430,000 years ago. Researchers who examined the scattering patterns of the remains at both the Rising Star cave system in Africa and the Sima de los Huesos site in Spain (Egeland et al. 2018) concluded that the sites showed evidence of having been scavenged but that this doesn’t disprove the possibility that they may also be deliberate burials. The verdict is still out on this. Lee Berger and other scientists are conducting further investigations of the H. naledi skeletal deposits to further explore the possibility they might be evidence of something more deliberate than the actions of predators.

Homo neanderthalensis

The word “Neanderthal” might conjure up stereotypical images of a brutish caveman-like creature holding a club in one hand and dragging supper with the other. No one said entertainment had to be scientifically accurate, but media can create false perceptions and stereotypes about the past. This section takes a closer look at who the Neanderthal people were and the role they played in the human story.

Figure 5.20 Distribution map of Neanderthal sites. The red squares mark locations of Neanderthal remains and the shaded area represents the supposed territory of Neanderthal people in Europe and Asia. (credit: modification of work Neanderthal distribution by Berria/Wikimedia Commons, CC BY-SA 4.0)

Neanderthals have been found only in regions of Europe and the Middle East and are dated to between about 400,000 and 40,000 years ago. The first fossils, which were found in the Neander Valley, were believed to be the remains of an extinct kind of human. The Germans called them the Neanderthals, the people of the Neander Valley.

Figure 5.21 The Neanderthal skull on the left is noticeably different from the H. sapiens skull on the right. (credit: (left) Jose-Manuel Benito/Locutus Borg/Wikimedia Commons, Public Domain; (right) “Image from page 27 of “Human physiology” (1907)” by Furneaux, William S/Internet Archive Book Images/flickr, Public Domain)

Neanderthals possess several distinctive anatomical characteristics: the skull and brain is larger than that of humans, with an average size in Neanderthals of 1,520 cc compared to modern humans’ 1200–1400 cc. Does the Neanderthal’s larger brain size mean that it was more intelligent than modern humans? As mentioned earlier in this chapter, while there does seem to be a correlation between brain size and complex cognitive skills, the brain in some hominins may have been organized differently than that of modern humans, with different anatomical areas of the brain emphasized. It is believed that in the Neanderthal brain, the frontal region, which is the center of speech and language, was less developed, while the back of the brain, which deals with the senses, was more developed. This greater development in the back area of the brain could be a survival adaptation found in Neanderthals who had to hunt in often harsh and difficult conditions.

Philip Lieberman, a cognitive scientist at Brown University, argues that Neanderthals lacked the anatomy necessary for humanlike speech. He drew this conclusion based on a reconstruction of a Neanderthal throat, which indicated that the neck could not accommodate the vocal apparatus of modern humans (Lieberman,P. 2007). While there is evidence of a hyoid bone, a small horseshoe-shaped bone in the front of the neck, that would have been able to anchor the tongue muscles, other anatomical evidence suggests that the larynx in Neanderthals was placed high in the throat. A highly placed larynx limits an animal’s ability to produce many sounds, such as vowels. In humans, the larynx is positioned further down into the throat. The Neanderthal has been determined to have possessed the gene FOXP2, which is linked to the ability to understand complex language, but the verdict is still out as to whether they were able to produce complex language. It is believed by some researchers that the ability to produce complex speech gave H. sapiens a significant edge over the Neanderthal.

Other skull characteristics of the Neanderthal include an occipital bun at the back of the skull (as also seen in H. antecessor and H. erectus), large brow ridges (which are not solid bone and create an air cavity), a large nasal cavity, and incisors that show a rounded pattern of wear, especially in older individuals. Their large front teeth typically show excessive wear. Chipping and pitting on the incisors are believed to have been caused by chewing on leather. The postcranial bones show that they had a broad scapula, which indicates that their rotator cuff muscles were well developed. They possessed a robust humerus with a massive head and the ability to rotate their arms, which suggests they were capable of throwing projectiles and using spears.

Some of the best-known Neanderthal specimens come from a place called Shanidar Cave in Iraq. Within this cave, various skeletal remains of eight individual Neanderthals were found. These remains are identified as Shanidar 1–9, which were discovered between 1957 and 1961, and Shanidar 10, which was discovered in 2006. Nearly all the skeletal remains show some evidence of trauma, suggesting that hunting was risky business. At various Neanderthal sites it has been observed that men and women exhibit similar cranial injuries, suggesting that women might have also engaged in hunting activities. However, the number of injuries in women were significantly fewer than those found in men (Beier et al. 2008). In a comparative study, it was established that during the Upper Paleolithic, modern H. sapiens sustained similar injuries as the Neanderthal, but interestingly, these injuries were less likely to result in death (Beier et al. 2008).

Shanidar 3 features a 40-to-50-year-old Neanderthal man who suffered a rib injury, potentially as the result of an encounter with an animal, and suggests healing as a result of care from others. Shanidar 1, called the “Old Man” (30–45 years old was old in Neanderthal terms), had multiple traumas to his body, one of which resulted in blindness in one eye. He was also missing the lower part of his right arm and hand, which suggests the earliest amputation on record. Although he did heal from this amputation, it may have left him paralyzed on the right side of his body. He also had no teeth. It is believed he was kept alive by taking food that had been chewed by others for him. There is evidence of many of these individuals healing from their injuries, which suggests that compassion and a sense of social responsibility for disabled members of the community existed.

Figure 5.22 This cave is the site of the Shanidar 4 Neanderthal flower burial site. Evidence found here and at other sites indicates that the Neanderthal practiced intentional burials of their dead. (credit: “Shanidar Cave, Iraqi Kurdistan” by Sammy Six/flickr, CC BY 2.0)

The Flower Burial Hypothesis

The remains found at Shanidar 4 in Iraq suggest that the Neanderthal practiced intentional burials, or deliberate placing of the dead in a ritualistic manner. At Shanidar 4, the individual is placed on his left side with his legs drawn up in a flexed position. Pollen analysis of the soil surrounding the corpse suggests that spring flowers had been placed in the grave, possibly indicating that the Neanderthal had a belief in an afterlife and established mortuary practices. However, there has been a lot of debate as to whether there is sufficient evidence to conclude that that the pollen found at some of the Neanderthal sites was a result of ritualistic placement of flowers. Opposing hypotheses propose that the pollen was brought into the cave and deposited by burrowing rodents (Sommer 1999). In spite of these counterclaims, the consensus supports the theory that the Neanderthal did practice intentional burials. This is largely based on evidence such as the careful placement of bodies in specially dug shallow pits. Recent research at both Shanidar Cave and other sites now support the claim that the Neanderthal did practice ritual and intentional burial.

Figure 5.23 This reconstruction of a Neanderthal grave is housed in the Israel Museum in Jerusalem. (credit: “Neanderthal Burial, Cast” by Gary Todd/flickr, Public Domain)

Neanderthal Creativity and Material Culture

Neanderthals have been labeled, perhaps unjustly, as a species with a limited ability to communicate in symbolic or abstract forms. Until recently, the Neanderthal had been assumed to lack the cognitive skills associated with the practice of ritual and art. However, cave paintings discovered in Spain in 2012 by Alistair Pike, an archaeologist at the University of Southampton, UK, challenge that assumption. These paintings, which have been dated to around 65,000 years ago, before the arrival of H. sapiens in the region, have been determined to be the creative works of the Neanderthal and are currently considered the oldest cave art ever found. This discovery may change what people have previously thought about Neanderthal cognition and their ability to express symbolic thought. It should be acknowledged that the ability to depict the world evident in these paintings does not compare with that in the artwork from H. sapiens sites like Chauvet and Lascaux in France (to be discussed later in this chapter).

Neanderthals created more technologically advanced tools than those produced by H. erectus and seen in the Acheulian tool industry. The tool industry associated with the Neanderthal hominins is called the Mousterian tool industry or the Middle Paleolithic tool industry. Archeological sites that date to the Neanderthal period are dominated by flake tools. This means that the Neanderthal struck flakes from cores and then used the flakes as their tools instead of the core. This resulted in smaller and sharper tools with increased utility.

What Happened to the Neanderthal? What Gave Modern Humans the Edge?

The Neanderthal went extinct around 35,000 to 50,000 years ago. There have been various hypotheses as to what caused this, many connected to the fact that Neanderthal coexisted with H. sapiens in regions of Europe and Asia for an estimated 2,600–5,400 years. These hypotheses include an inability to adapt to a changing climate and colder temperatures, the spread of disease, competition for food with H. sapiens, and even aggressive takeover by the H. sapiens, who may have been better able to adapt to environmental changes due to more complex technology and language skills. Another theory points to evidence that the Neanderthal tended to live in small, scattered groups with limited genetic diversity and low birth rates, which potentially impacted the ability of the Neanderthal to be competitive. A low gene pool can result from reduced birth rates and low survival rates of young children. New genetic evidence shows that the Neanderthal were genetically less diverse and more isolated than H. sapiens. And then some argue that the Neanderthal didn’t go extinct at all because some people still have Neanderthal genes in them.

Are You a Neanderthal?

Recent genetic evidence indicates that human-Neanderthal interbreeding was happening as far back as 125,000 years ago. From one Neanderthal toe bone found in the Denisova cave in Siberia Russia, the Max Planck institute has been able to produce a whole genome which revealed evidence of inbreeding amongst the Neanderthal, along with interbreeding with their cousins the Denisovans (discussed further in next section), as well as a mystery yet to be identified species, as well as Homo sapiens (Pennisi, E., 2013). The genetic evidence is most prominent in people of East Asian descent, accounting for between 2.3 percent and 2.6 percent of their DNA. Various mutations and diseases are linked to this Neanderthal DNA, including diabetes, addictions, depression, allergies, and Crohn’s disease. One study suggests that Neanderthal genes gave people some level of protection from getting a severe case of COVID-19 (Huber, J., 2018), although a later study (Zeberg and Pääbo 2020) proposes that Neanderthal genes may have increased the risk of respiratory failure as a result of the COVID-19 virus. Such differences may have to do with different genetic clusters in Neanderthal populations in different geographical regions (Mortazavi et al. 2021). Neanderthal genes are believed to have provided immunity to some viruses that H. sapiens, arriving from Africa, would not have had time to build up an immunity against. On the reverse side, H. sapiens may have brought diseases from Africa that the Neanderthal did not have resistance to, possibly playing a role in their extinction. As Janet Kelso, a computational biologist at the Max Plank Institute for Evolutionary Anthropology, states, “Viral challenges, bacterial challenges are among the strongest selective forces out there” (Akst, 2019).

The Hobbit of Flores

Homo floresiensis, also known as “the Hobbit” or “Flores Man,” was discovered on the island of Flores in Indonesia in 2003. The species has been dated to approximately 100,000–60,000 years ago. What was surprising about this species is its size. An adult individual stood about 3 feet 7 inches tall. Liang Bua, the cave where H. floresiensis was found, shows evidence of the use of fire for cooking and contains bones with cutmarks. Since the initial discovery, partial skeletons of nine individuals have been found.

H. floresiensis, like the earlier hominins, did not possess a chin, and its leg bones are thicker than those of modern humans. They had flat feet that were relatively long in comparison to the rest of their bodies. As a result of these anatomical differences, it is believed that their bipedalism was quite different from that of modern humans, with a high stepping gait and slower walking speed. H. floresiensis also had substantially more mobility in the elbow joint, which suggests that they were tree climbers.

Their small brain size is not believed to have affected their intelligence. This challenges the view that larger cranial capacity equals higher cognitive skills. Although H. floresiensis has a brain size of just 380 cc, equal to the size of an orange, evidence indicates that they made tools, used fire, and hunted very much like H. erectus. The brain of H. floresiensis does contain a Brodmann area, which is associated with cognitive abilities, that is the same size as that found in modern humans.

Some have suggested that H. floresiensis is a sister species of Homo habilis that branched off before or shortly after the evolution of Homo habilis. Other hypotheses suggest that they were the descendants of H. erectus who became stranded on the island after arriving via water, possibly on bamboo rafts.

Another Homo species similar in size to H. floresiensis was H. luzonensis, found on the island of Luzon in the Philippines and dated to at least 50,000–67,000 years ago. H. luzonensis displays a hybrid of australopithecine traits (including curved hands and feet) and Homo characteristics, yet lived alongside modern H. sapiens. Clearly the genus Homo is more diverse and complex than was originally thought, especially within the special evolutionary pressures of island environments.

Figure 5.24 This H. floresiensis skull is on display at the Naturmuseum Senckenberg, a Natural History Museum in Germany. (credit: Daderot/Wikimedia Commons, Public Domain)

Island Dwarfism as an Evolutionary Explanation

Numerous hypotheses have been proposed to account for the small brain size found in both H. floresiensis and H. luzonensis. One initial theory was that H. floresiensis had microcephaly, which is a genetic condition creating an abnormally small head. This was discounted as an explanation once additional specimens were found exhibiting the same size. Perhaps the most convincing explanation is an evolutionary theory called island dwarfism, which notes that the evolutionary pressures on islands can be very different from those found on the mainland. Island dwarfism posits that mainland small animal species that colonize islands might evolve larger bodies if the island does not contain key predators. On the other hand, larger species may become smaller due to more limited resources in an island environment. According to the island dwarfism hypothesis, H. erectus made its way to Flores, where its descendants became isolated and grew progressively smaller to make the most of limited resources in the island environment. This theory is supported by the fact that there are unique sizes displayed by other animals found with H. floresiensis, including a dwarf species of primitive elephant called a Stegodon. As H. floresiensis’s body shrank, its brain may have undergone “neurological reorganization” to fit a smaller cranial space while maintaining its brain-to-body ratio. The only potential large predator that may have been a threat to H. floresiensis was the Komodo dragon, which ate most of the large mammals on the island. Nevertheless, predation pressures for the little people were likely quite low—that is, until H. sapiens arrived.