In his series on human origins for the BioLogos Forum, biological anthropologist James Kidder has explored topics from the advent of bipedality to the rise of human precursors australopithecines and earlyHomo sapiens. In posts yesterday and today, Kidder focuses on the discovery of Neandertals and the behavioral and morphological changes that gave rise to what might be our closest evolutionary relatives.
Changes From Early Archaic Homo sapiens:
Several distinct evolutionary adaptations are present in Neandertals compared to their precursors. There is an increase in the size of the head, such that, by the time of the classic Neandertals of Western Europe, brain size averages 1550 cubic centimeters, up from the early archaic Homo sapiens average of 1225 ccs. What is also notable about this is that it is approximately 100 ccs larger than that of modern humans. This particular trait is still poorly understood but may be a by-product of the systemic adaptations to the cold weather.
Another change is evident in the cranial expansion and reorganization that is exemplified by a view from the rear of the vault. In Homo erectus and early archaic Homo sapiens, the maximum breadth of the cranium was roughly at the level of the ears, but by the time of the Neandertals, it had moved up toward the middle of the vault. This gave the cranium a round shape, described by the French anthropologists of the early 20th century as “en bombe.” Thus, while the maximum width of the vault did not change, the overall size of the brain did. The angular torus, the ridge of bone extending from the ear to the back of the head, characteristic of Homo erectus, is now gone and the overall rear of the vault is more rounded with a pronounced “bun.”
In the front of the head, the brow ridges above the eyes, while being as large as those inHomo erectus, are now bifurcated, with a distinct depression above the nose. Further, from the early to the late Neandertals, there is a thinning of this ridge, suggesting a relaxation of selection pressures for its presence over time. The back teeth continue to get smaller, while the front teeth remain unchanged from the early archaics. Below the eyes, the infraorbital plates swing out, appearing as if someone had simply grabbed the nose and pulled. This is known as “midfacial prognathism.” Hypotheses have been proposed to explain this morphology, the most promising of which is that it is an adaptation to cold air. Given that the average daily temperature during much of the Early Würm was considerably lower than that of today, it has been suggested that, in order to bring the cold air up to blood-temperature levels, more space between the entrance to the nose and the brain would have been necessary. As the late Pleistocene wore on, Neandertal noses continued to increase in size.
As much as these cranial characteristics help to define Neandertals, however, there are striking changes in the post-cranium, as well. It is widely thought that these changes can at least partly be explained by two prevailing “rules” that govern body form in organisms. The first of these is Bergmann’s Rule, which posits that animal species will, over time, adapt, evolutionarily, to changes in temperature by either getting larger (cold weather) or smaller (warm weather). Just as a large piece of meat on a plate will take longer to cool down than a smaller piece, the purpose of increasing or decreasing size is to maximize or minimize heat retention.
The second rule is Allen’s Rule. This states that animals will maximize or minimize their surface area in response to heat or cold. For example, individuals of population groups in very cold areas tend to be shorter and stockier than those found in tropical locales. The less surface area that is exposed, the greater the ability to retain heat. The warmer the area, the longer the limbs tend to be. This allows more radiation of heat from the body.
The overall morphology of Neandertals conforms to these two rules, reflecting their adaptation to the extreme cold of Europe. In contrast to the early archaic Homo sapiens, the Neandertal trunk becomes shorter and the chest develops a “barrel” appearance. Additionally, the ends of the long bones (the humerus, radius, ulna, femur, and tibia) become shortened, as if someone had simply taken a chunk out of them toward the end. Neandertal height is also shorter than modern humans (males average 5 feet 4 inches and females 5 feet) and even late-surviving Homo erectus from Africa and Asia, and the long bones also have a characteristic bowing to them with very strong muscle markings. The overall appearance is one of compactness.
Important Neandertal Discoveries:
Beginning with the advent of Neandertal discoveries in the early 1800s, there has been a steady stream of finds to the present day. These can be broken down into three generally accepted periods: early, classic, and late.
Early Period Neandertals
The early Neandertals, which appear around 120,000 years ago, are represented by the fossils finds from Ehringsdorf in Germany, Saccopastore in Italy, and Krapina, in the Pannonian Basin of Central Europe three sites that are widely spread geographically. This suggests a selective advantage for this morphology and that there was major population radiation of it throughout Europe.
The best representative of this period is from the site of Saccopastore. Two crania from this site, near Rome, were discovered between 1929 and 1935. The date for these finds is uncertain but they are thought to be either from the Riss/Würm interglacial period or the early Würm, which would put them at between 120-125 thousand years B.P. (Spencer, 1997)
The Saccopastore 1 cranium (Figure 4) is mostly complete and displays very large brow ridges, a low, sloping forehead and a rounded back of the vault. This cranium shows the beginnings of the expanded midface, with large front teeth and nose that becomes prevalent in later Neandertals.
Aside from the previously mentioned La Chapelle Neandertal, others of this time period come from the sites of Le Moustier, La Ferrassie, Gibraltar (Forbes Quarry), Monte Circeo (Guattari Cave), Spy and the hypodigm specimen from the site of Neandertal. All of the specimens from these site levels are thought to date from between 70 and 50 thousand years B.P.
Along with the La Chapelle Neandertal, perhaps the best example of this period is the complete adult cranium of La Ferrassie 1 (Figure 5). This was discovered in 1909 and is thought to be approximately 70 thousand years old. It has the characteristic occipital bun, flattening of the rear of the vault, sloping forehead, large brow ridges, and very large face. While these features are variable in other classic Neandertals, in La Ferrassie 1, they are all there to a significant degree.
Late Period Neandertals
The late period Neandertals date from between 50 thousand down to around 27 thousand years ago and much emphasis has been placed on them in drawing inferences as to the relationship between Neandertals and modern humans. This group is represented principally by the Neandertal finds from the French sites of St. Cesaire, Arcy Sur-Cure, the Czech site of Vindija, and the Spanish site of Zafarraya. These Neandertals are characterized by a general reduction of traits that typify the classic Neandertals.
The best example of this group is from the site of St. Cesaire (Figure 6) in southwestern France, in the Charente-Maritimes district. Found in 1979, the find is thought to be between 40 and 41 thousand years old (Hublin et al., 2012). This Neandertal, while having some mid-facial prognathism has a generally flatter face and has a tooth-row that is reduced in size over the classic Neandertals. Additionally, while not prominent, there is a small chin, a characteristic that is present only in modern humans as a group. On the other hand, the brow ridges are very distinct, the forehead slopes back from glabella and the eye orbits and nose are quite large.
Of additional importance is the Zafarraya Neandertal, discovered in Northern Spain. The main find from this site is a mandible that exhibits classic Neandertal characteristics, having no chin, large front teeth in relation to back teeth, and a long dental arcade. The mandible is dated by Uranium/Thorium to slightly younger than 30,000 years B.P.
This is of critical importance because the earliest demonstrably modern humans in Europe are from the Moravian karst region of the Pannonian basin in central Europe, from the site of Mlade and date to the Early Würm/Late Würm interglacial—between 34 and 37 thousand years B.P. Other modern human finds from France and Germany have also been dated to between 30 and 32 thousand years B.P. This puts the Zafarraya Neandertal (and possibly St. Cesaire as well) in the overlap period with the earliest moderns. It has, consequently, been thought that these Neandertals represent very late-surviving refugia populations and they have figured into replacement models of modern human origins. These will be addressed in the next post.
Neandertal Tool Technology
As time wore on, the stone tool technologies of archaic Homo sapiens began to expand and they began to innovate from the basic hand axe template. While the hand axe was the hallmark of Homo erectus, archaic Homo sapiens began to experiment with scrapers. The critical cognitive shift was the move away from “core” tools to “flake” tools—using the core as a basis for the stone tool, not the tool itself. To this end, they invented, and perfected a stone tool creation method known as the Levallois technique (Figure 7). This was truly ingenious. First, a large, relatively flat core was found . Then the sides were punched out . Once this was done, the modified core was turned on its side and flakes were knocked off . Then large flakes were removed in a sideways fashion [5 and 6]. This could be done in assembly-line fashion and produced two kinds of tools, the larger tools shown in  and the smaller, blade-like tools that were punched out. It is not entirely clear where or from what this stone tool technology evolved, although most view it as a radical re-envisioning of the blank used to make hand axes.
Recently, it has been discovered that Neandertals also created bone tools. Working at the site of Pech-de-l’aze, research teams from the Max Planck Institute have discovered what they interpret to be lissoirs, or leather-working tools (Figure 8). The making of bone tools has been, up to now, associated with only anatomically modern Homo sapiens and this discovery suggests that Neandertals were capable of a wide range of tool-making behavior, despite the inhospitable conditions. Further, these researchers suggest that these tools may have originated with Neandertals. Marie Soressi, of Leiden University is quoted as saying:
“If Neandertals developed this type of bone tool on their own, it is possible that modern humans then acquired this technology from Neandertals. Modern humans seem to have entered Europe with pointed bone tools only, and soon after started to make lissoirs. This is the first possible evidence for transmission from Neandertals to our direct ancestors.”
Neandertal Burials and Social Behavior:
Another aspect of Neandertal existence that sheds some light on their situation is the considerable evidence that they buried their dead in ways that suggested an understanding, not just of death, but perhaps the significance of what death meant and how important life was. These burials have been found, principally, at La Chapelle, and La Ferrassie in Europe, Kebara, in the Levant, and Shanidar Cave, in Iraq, of which the discoverer, Ralph Solecki remarked “…although the body was archaic, the spirit was modern” (Solecki, 1971). They consist primarily of capstones, bodies placed in flexed positions, and bodies placed with flower arrangements (Leroi-Gourhan, 1975; Smirnov, 1989). Further, as is evident from the site of Dederiyeh Cave, in Syria and Teshik-Tash in Russia, infants were treated with extreme care and given their own burials (Dodo, Kondo, Muhesen, & Akazawa, 2002).
Another example of behavior that we typically only associate with modern humans is care for the infirm. At the Neandertal site of Shanidar Cave, in Iraq, several individuals suffered what were clearly injuries that would have led to that person having limited motor and mobility capabilities. Trinkaus and Zimmerman write:
However, these considerations also imply that the Neandertals had achieved a level of societal development in which disabled individuals were well cared for by other members of the social group. All of these individuals show extensive healing of their injuries, usually with little or no evidence of infection. Several of them, particularly Shanidar 1 and 3, lived for many years with severe disabling conditions, which would have prevented them from actively contributing to the subsistence of the local group. (Trinkaus & Zimmerman, 1982)
What comes next is the most contentious section in all of palaeoanthropology—the origins of modern humans. As we saw from Boule’s example, this is a study that is fraught with high emotion and strong opinions. As Christians, however, we have an added stake in the matter. Before us is the thorny question of whether or not these Neandertals, in any way, gave rise to us. If they did to any significant degree, then it perhaps forces us to consider how closely our genetic history is tied to questions about human uniqueness and the image of God.
Furthermore, as we inch toward our own species, it is becoming increasingly clear that these Neandertal precursors acted, in many ways, like us, and were it not for the crushing weight of the glacial conditions, might have excelled in more ways than what we see. This perhaps forces us to consider whether aspects of human culture are all that unique as well.