Homo erectus in Middle East / Emergence of “Fat Hunters”

New ideas on Homo erectus and an evolutionary shift to “a new hominin lineage” in the Middle East. 

Go to original paper for details and much more…

See also an interesting commentary on H. erectus by John Hawks

http://johnhawks.net/weblog/reviews/erectus/changing-height-homo-erectus-2010.html

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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0028689

Man the Fat Hunter: The Demise of Homo erectus and the Emergence of a New Hominin Lineage in the Middle Pleistocene (ca. 400 kyr) Levant

  • Miki Ben-Dor, Avi Gopher, Israel Hershkovitz, Ran Barkai
  • Published: December 9, 2011

Introduction

It is our contention that two distinct elements combined in the Levant to propel the evolutionary process of replacing H. erectus by a new hominin lineage ([1], As the classification of varieties of the genus Homo is problematic, we refrain in this paper from any taxonomic designations that would indicate species or subspecies affiliation for the hominins of Qesem Cave. (Thank-you!) 

The Qesem Cave hominin, based on the analysis of teeth shares dental characteristics with the Skhul/Qafzeh Middle Paleolithic populations and to some extent also with Neandertals). One was the disappearance of the elephant (Elephas antiquus) – an ideal food-package in terms of fat and protein content throughout the year – which was until then a main calorie contributor to the diet of the H. erectus in the Levant. The second was the continuous necessity of H. erectus to consume animal fat as part of their diet, especially when taking into account their large brains [2]. The need to consume animal fat is the result of the physiological ceiling on the consumption of protein and plant foods. The obligatory nature of animal fat consumption turned the alleged large prey preference [3], [4] of H. erectus into a large prey dependence. Daily energy expenditure (DEE) of the hominins would have increased when very large animals such as the elephant had diminished and a larger number of smaller, faster animals had to be captured to provide the same amount of calories and required fat. This fitness pressure would have been considerably more acute during the dry seasons that prevail in the Levant. Such an eventuality, we suggest, led to the evolution of a better equipped species, in comparison with H. erectus, that also had a lighter body [5], a greater lower limb to weight ratio ([6]:194), and improved levels of knowledge, skill, and coordination ([7]:63) allowing it to better handle the hunting of an increased number of smaller animals and most probably also develop a new supporting social organization. (Chicken or egg? Did the environmental change “promote” a newer, leaner, more coordinated version of Homo erectus, or did a “new hominin” move in from elsewhere?)

We also suggest that this evolutionary process was related to the appearance of a new and innovative local cultural complex – the Levantine Acheulo-Yabrudian [8], [9]. Moreover, a recent study of dental remains from the Acheulo-Yabrudian site of Qesem Cave in Israel dated to 400-200 kyr ago [10], [11] has indicated that the hominins inhabiting the cave were not H. erectus but were rather most similar to later populations (e.g., Skhul/Qafzeh) of this region ([1] and references therein).

The Broader Context

Our direct ancestor, H. erectus, was equipped with a thick and large skull, a large brain (900 cc on average), impressive brow ridges and a strong and heavy body, heavier than that of its H. sapiens successor (e.g., [12], [13], [14]). Inhabiting the old world for some 1.5 million years, H. erectus is commonly associated with the Acheulian cultural complex, which is characterized by the production of large flakes and handaxes – large tools shaped by bifacial flaking. Handaxes are interpreted as tools associated with the butchering of large game (e.g., [15], [16]). H. erectus was also suggested in recent years to have used fire [17], [18]; however the supporting evidence is inconclusive. Albeit the positive archaeological evidence from the site of Gesher Benot Ya’aqov (henceforth GBY) dated to around 780 kyr [19], [20], [21], the habitual use of fire became widely spread only after 400 kyr [22], [23], [24], [25].

Archaeological evidence seems to associate H. erectus with large and medium-sized game {Namely, Body Size Group A (BSGA Elephant, >1000 kg), BSGB (Hippopotamus, rhinoceros approx. 1000 kg), and BSGC (Giant deer, red deer, boar, bovine, 80–250 kg); (after [26])}, most conspicuously elephants, whose remains are commonly found at Acheulian sites throughout Africa, Asia, and Europe (e.g., [26], [27], [28], [29], [30]). In some instances elephant bones and tusks were also transformed into shaped tools, specifically artifacts reminiscent of the characteristic Acheulian stone handaxes [31].

In Africa, H. sapiens appears around 200 kyr ago, most probably replacing H. erectus and/or H. heidelbergensis [32], [33], [34]. Early African H. sapiens used both handaxes and the sophisticated tool-manufacturing technologies known as the Levallois technique (e.g., [35], [36]) while its sites are devoid of elephants [32], [35]. The presence of elephants in many Acheulian African sites and their absence from later Middle Stone Age sites [29], [37], evoked an overkill hypothesis ([38]:382), which was never convincingly demonstrated. Thus no link was proposed, in the case of Africa, between human evolution and the exclusion of elephants from the human diet, and no evolutionary reasoning was offered for the emergence of H. sapiens in Africa [39].

In Europe, H. erectus was replaced by H. heidelbergensis [40] and later by hominins associated with the Neanderthal evolutionary lineage [41]. In spite of significant cultural changes, such as the adoption of the Levallois technique and the common use of fire, the manufacture and use of handaxes and the association with large game persisted in post-erectus Europe until the demise of the Neandertals, around 30 kyr BP (e.g., [42]). H. sapiens did not evolve in Europe but migrated to it no earlier than 40 kyr BP (e.g., [43]).

In the Levant, dental remains from the Acheulo-Yabrudian site of Qesem Cave, Israel [10], [11] demonstrate resemblance to dental records of later, Middle Paleolithic populations in the region [1] indicating that H. erectus was replaced some 400 kyr ago by a new hominin ancestral to later populations in the Levant. A rich and well-dated (400-200 kyr) archaeological dataset known from the Levant offers a glimpse into this significant process and a better understanding of the circumstances leading to the later emergence of modern humans thus suggesting a possible link between the cultural and biological processes. This dataset pertains to the unique local cultural complex known as the Acheulo-Yabrudian, a diversified and innovative cultural complex (e.g., [8], [44], [45]), which appeared some 400 kyr ago, immediately following the Acheulian cultural complex [10], [11], and which lasted some 200 kyr. Acheulo-Yabrudian sites as well as sites associated with subsequent cultures in the Levant show no elephant remains in their faunal assemblages.

Conclusion

For more than two decades a view dominated anthropological discussions that all modern human variation derived from Africa within a relatively recent chronological framework. Recent years challenged this paradigm with new discoveries from Europe, China, and other localities, as well as by new advances in theory and methodology. These developments are now setting the stage for a new understanding of the human story in general and the emergence of modern humans in particular (e.g., [1], [39], [132], [133], [134], [135], [136], [137], [138], [139], [140], [141], [142], [143], [144], [145], [146]). In this respect, the Qesem hominins may play an important role. Analysis of their dental remains [1] suggests a much deeper time frame between at least some of the ancestral populations and modern humans than that which is assumed by the “Out of Africa” model. This, combined with previous genetic studies (e.g., [147], [148], [149], [150]), lends support to the notion of assimilation (e.g., [144]) between populations migrating “out of Africa” and populations already established in these parts of Eurasia.

It is still premature to indicate whether the Qesem hominin ancestors evolved in Africa prior to 400 kyr [136], developed blade technologies [151], [152], and then migrated to the Levant to establish the new and unique Acheulo-Yabrudian cultural complex; or whether (as may be derived from our model) we face a local, Levantine emergence of a new hominin lineage. (If it’s local, from which species did the “new hominin” evolve? Is this the putative location where H. erectus “became” H. sapiens?) The plethora of hominins in the Levantine Middle Paleolithic fossil record (Qafzeh, Skhul, Zuttiyeh, Tabun) and the fact that the Acheulo-Yabrudian cultural complex has no counterparts in Africa may hint in favor of local cultural and biological developments. This notion gains indirect support from the Denisova finds that raise the possibility that several different hominin groups spread out across Europe and Asia for hundreds of thousands of years, probably contributing to the emergence of modern human populations [153], [154], [155].

It should not come as a surprise that H. erectus, and its successors managed, and in fact evolved, to obtain a substantial amount of the densest form of nutritional energy available in nature – fat – to the point that it became an obligatory food source. Animal fat was an essential food source necessary in order to meet the daily energy expenditure of these Pleistocene hominins, especially taking into account their large energy-demanding brains. It should also not come as a surprise that for a predator, the disappearance of a major prey animal may be a significant reason for evolutionary change. The elephant was a uniquely large and fat-rich food-package and therefore a most attractive target during the Levantine Lower Palaeolithic Acheulian. Our calculations show that the elephant’s disappearance from the Levant just before 400 kyr was significant enough an event to have triggered the evolution of a species that was more adept, both physically and mentally, to obtain dense energy (such as fat) from a higher number of smaller, more evasive animals. The concomitant emergence of a new and innovative cultural complex – the Acheulo-Yabrudian, heralds a new set of behavioral habits including changes in hunting and sharing practices [9], [23], [45] that are relevant to our model.

Thus, the particular dietary developments and cultural innovations joined together at the end of the Lower Paleolithic period in the Levant, reflecting a link between human biological and cultural/behavioral evolution. If indeed, as we tried to show, the dependence of humans on fat was so fundamental to their existence, the application is made possible, perhaps after some refinement, of this proposed bioenergetic model to the understanding of other important developments in human evolutionary history.

 

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