Part II
Dr. Amanuel Beyin at an excavation site.
Issayas: What is the importance and evidences of first human
exploitation in the marine resources at the coast of the Red sea such
places as Asfet, Gelealo NW, Mise East (the sites where you studied for
your PhD research), Abdur and etc.?
Dr. Amanuel: As we all
know, Eritrea was at war during most of the seminal years in the history
of archaeological research in East Africa, 1960’s to the 80’s. As such,
much of Eritrea’s coastal territories had seen little prior research
due to protracted political instability and environmental adversity of
the region. The first archaeological evidence for prehistoric human
adaptation along the Eritrea coast has come from the site of Abdur
(eastern coast of the Gulf of Zula), where a geological survey in the
late 1990’s documented stone tools embedded in a coral reef deposit
dating to ~125,000 years ago.
The Abdur evidence suggests the presence
of coastal adaptation by African hominids along the Red Sea coast prior
to the generally accepted date for Homo sapiens dispersal out of
Africa. The association of artifacts with oysters, shellfish and
terrestrial mammals at Abdur has suggested to researchers a mixed
subsistence strategy, involving beach-combing, and hunting terrestrial
game along the shorelines of the Gulf. Stimulated by the Abdur
discovery, in May 2005, my adviser and I set out to conduct a pilot
archaeological exploration on the southern peripheries of the Gulf of
Zula and interior plains of the Buri Peninsula, to further assess the
archaeological potential of the landscapes outside of the Abdur
proximity. The survey documented more than a dozen sites from near
coastal and inland contexts representing different age ranges. In two
subsequent field seasons, my team (
all Eritreans) conducted intensive
survey and excavation at three sites: Asfet, Gelalo NW and Misse East.
The Asfet site produced stone tools, based on typological attributes,
are believed to date to between 100,000 – 50,000 years ago. The other
two sites, Gelalo and Misse produced stone tools in association with
mollusk shells (presumably food refuse) dated to between 8000 and 5000
years ago.
Asfet setting off the coast of the Gulf of Zula
Gulf of Zula and Buri Peninsula
Dr. Amanuel surveying
Asfet, Eritrea. 2006.
Asfet
Public outreach with local elders at Gelalo.
Eritrean field crew at Gelalo site, Eritrea in 2006.
All in all, the evidence suggests the presence of
intermittent human settlement in the area, ranging in age 100,000 - 5000
years ago.
The Asfet stone tool assemblage is particularly important
because it represents an archaeological culture (referred to as Middle
Stone Age) associated with the Homo sapiens populations that are
believed to have launched successful dispersal out of Africa. The
evidence reinforces the Abdur discovery in confirming the presence of
coastal adaptation by African hominids along the Red Sea coast prior to
their dispersal out of Africa. Whether the Asfet and Abdur hominids had
directly dispersed to Arabia or Eurasia is difficult to prove. It is
still possible that these hominids had returned to the hinterlands of
the Horn once living around the coast became precarious for any reason,
but at least one of the contemporary or descendant hominids must have
made the long trek to Asia. In a broader anthropological context, the
evidence attests the degree of our ancestors’ adaptive acuity in
occupying such a strategic area where they could maximize their survival
chance by exploiting both marine and terrestrial resources. This acuity
was a necessary prerequisite for our ancestors’ subsequent evolution
into a culturally more complex species, capable of colonizing all of
earth’s frontiers…and possibly other planets, soon!
Issayas: If
I am not mistaken, you are studying the stone industries and varied
shell types from the above sites in coastal Eritrea to understand the
Human behavior, the paleo-environment and paleo-ecology. How does one
understand the behavior and why do one need to understand the
aforementioned?
Dr. Amanuel: Yes, in my dissertation I reported
on a thorough description of the stone tool industries documented at
the three sites I mentioned above. The results of my work have been
published in peer reviewed journals and as a monograph (see a link to my
personal website below to find out more about my scholarly work). The
paleoenvironmental and paleoecological aspects have not been examined
yet. The diversity of stone tools at the sites is quite striking. We
have artifacts that look like they were used for butchering, as arrow
points and for piercing/slicing purposes. Often times, stone tools
represent the most common surviving evidence of human behavior at
archaeological sites, not just because they were the only tools humans
made, but they preserve better. By virtue of being rocks, they are less
susceptible to decomposition and alteration by weathering, unlike wood,
hide or fabric, which can easily decay. One way to reconstruct past
human behavior using stone tools is by examining the sources of the raw
materials used and the design aspects of the final products (variability
in shape and size of the tools). Stone tool making requires selecting
suitable raw materials and an understanding of the fracture mechanics of
each rock type. The Asfet inhabitants utilized about seven rock types,
each of which has its advantages and disadvantages. For example,
obsidian, a modestly utilized rock at Asfet, is brittle and can produce
flakes with sharp edges. However, it is a very dangerous rock during
knapping. The sharp flakes and shatters can cut through the skin of
one’s hand at a split of a second if you don’t understand how to
manipulate it. Other rocks are not as brittle as obsidian, but are safer
to manipulate and endure edge damage better (remember those tools can
get worn after repeated use). The majority of the rocks utilized at
Asfet appear to have been procured from the local exposures, meaning the
inhabitants did not transport the raw nodules for longer distances
(they were lucky!).
Asfet artifacts
 |
| Gelalo and Misse artifacts |
In
addition to utilizing a broad range of raw materials, the Asfet humans
produced a variety of tools, presumably to meet their daily survival
needs. For example, among the common tools we observe at Asfet are the
triangular points (see figure), which are usually associated with making
arrow points that could be used for hunting. Likewise, while the large
almond shaped hand axes are often interpreted as characteristic of meat
butchering and scraping activities, the pointed perforators (see figure)
are typically associated with piercing and drilling. The younger sites
of Gelalo and Misse are characterized by different toolkits,
collectively referred to as microliths because of their diminutive
nature. These tools appear to have been used as knives and inserts into
wooden shafts for making spears. The discovery of abundant stone tools
with design aspects indicative of hunting activity and a variety of
mollusk shells (large enough to be consumed as food) indicates that the
inhabitants of the Eritrean sites employed a broad subsistence strategy,
involving hunting terrestrial game and gathering aquatic resources from
the shoreline. By all accounts, we are looking at hunter-gatherers
that lived off of the blessings of nature. The same is true of those
hominids that spread out of Africa. It took several millennia after
these settlements for domestication/agricultural innovations to set off
in the region.
Issayas: How does your study contribute to the current knowledge of the Human evolution researches and dispersal?
Dr.
Amanuel: As I mentioned earlier, by virtue of its strategic location
along the Red Sea basin (one of the potential dispersal corridors for
early humans) and being part of the East African tropical ecosystem
(where Homo sapiens are believed to have first appeared), Eritrea
represents a critical region of East Africa in the ongoing human origins
research. Unfortunately, much of the coastal region had not seen
adequate research in the past. This has hindered a well-informed
assessment of the contribution of the region to human origins and
dispersal theories. The plain question I asked myself when developing
the project I described above was: what would be the contribution of
Eritrea to human origins and dispersal research? Of all the sites I
examined so far, the Asfet assemblage is particularly important in the
context of human origins or dispersal research. As noted above, the
assemblage broadly dates to 100,000 – 50,000 years ago, which is a
critical period in the evolution and dispersal of anatomically modern
humans out of Africa. The evidence exhibits reasonable affinity with
northeast African, the Nile Valley and Southern Arabian Middle Stone Age
Industries, which means that the inhabitants of Asfet had cultural and
biological (?) relationships with the hominids that left cultural and
fossil traces in those regions. We do not have hominid fossil remains
from Asfet or Abdur yet, but the artifacts are comparable with cultural
findings at other East African sites that yielded Homo sapiens fossils
(eg. Omo Kibish and Herto in Ethiopia). While much needs to be done to
fully understand the chronological and paleoenvironmental contexts of
Asfet, the evidence corroborates the plausibility of the region as a
potential refugium and departure point for early human dispersal.
Hunter-gatherers successfully adapted to coastal habitats along the
Eritrean coast may have served as source populations for the early
inhabitants of Arabia and Southeast Asia. Given the paucity of Stone Age
record from the western side of the Red Sea basin, the finding provides
a much needed reference datasets for future research in the region.
Even though there are only a few known coastal sites from the African
side of the Red Sea, it is likely the case that the coastal territories
of Eritrea and its neighboring regions (Sudan, Somalia and Djibouti)
were continuously visited by our early ancestors. Finally, the discovery
of the Asfet and Abdur Middle Stone Age sites from the Gulf of Zula
attests that numerous sites can be discovered along the African side of
the Red Sea basin by future systematic survey.
Issayas: How and when did the first human species spread from the African side of the Red Sea to the Asian side?
Dr.
Amanuel: It is not yet well understood as to how exactly early humans
dispersed from the African side to the Arabian side of the Red Sea, but
there are some hypotheses worth sharing. One hypothesis is that, they may
have used canoes or floating rafts to navigate the narrowest section of
the basin, which is located across the Strait of Bab el Mandeb. The
problem is that wood doesn’t preserve for a long time, so we can’t prove
this hypothesis. Alternatively, early humans could have swum the narrow
strait during periods of extreme low sea-level-stand. But, given the
violent wind currents across the strait, this view does not seem
plausible. Others have suggested the presence of episodic land-bridges
between the two sides of the basin. There is tangential evidence
supporting this view. A recent study of mtDNA variation among
southwestern Arabian and Horn of African baboon populations (Papio
hamadryas hamadryas) shows that the ancestral lineage of this species
originated in the Horn of Africa and entered Arabia in the time range of
200,000 – 80,000 years ago. The striking finding from the study is that
the SW Arabian hamadryas baboons are not related to any other baboon
populations in the northern parts of Arabia (meaning they don’t have
close relatives in the Middle East or northern Arabia). Based on this
observation, scientists suspect that the only way the ancestors of the
Arabian baboons could have reached the region is via temporary land
bridges formed during glacial maxima across the Red Sea (eg. Bab el
Mandeb). Hypothetically, the same route or land-bridge that the baboons
have used to enter Arabia must have been equally accessible to early
modern humans. One caveat with this scenario is that, marine isotopic
data shows that the Red Sea has not been severed from the Indian Ocean
for the past 400,000 years, which means, either the isotopic data is not
picking up some short-lived periods of disconnections between the two
bodies of water or there is something else we should know. Perhaps,
early humans used no other route except the Sinai land-bridge to
disperse out of Africa. Like any other scientific enterprise, the issue
of early human dispersal is full of unresolved riddles.
Front cover of Dr. Amanuel's new book.
When did
humans reach Arabia? I don’t have a definitive answer to the question,
but we know that human ancestors have continuously lived in that region
at least for the last one million years. Early humans and their
ancestors could have arrived there in waves, through either of the
potential routes mentioned above. Based on current genetic evidence, the
most successful wave of Homo sapiens migration into Arabia is believed
to have occurred ~ 75,000 years ago via the Bab el Mandeb. Some
researchers dispute this time frame in favor of earlier dispersal dates.
The artifacts from Arabian sites do show close resemblance with their
African counterparts, but it is not possible to determine dispersal or
arrival events based on cultural affinity alone. One culture can
disperse to a new environment after several millennia of its first
appearance at the source region. This topic being one of the hotly
debated issues in paleoanthropology, I rather not waste the reader’s
time with too many conjectures.
Issayas: Thank you for spending time from your busy schedule to answer my questions. Much appreciated.
Dr. Amanuel: Thank you for inviting me to offer my perspectives on this fascinating scientific topic.
All pictures are courtesy of Dr. Amanuel.
Below are links to various works of Dr. Amanuel and his website.
https://www.sites.google.com/a/asfet.net/amanuelbeyin/
http://www.usi.edu/libarts/socio/aybeyin.asp
http://www.academia.edu/530870/The_Bab_al_Mandab_vs_the_Nile-Levant_an_appraisal_of_the_two_dispersal_routes_for_early_modern_humans_out_of_Africa
http://www.academia.edu/954543/Early_to_Middle_Holocene_human_adaptations_on_the_Buri_Peninsula_and_Gulf_of_Zula_coastal_lowlands_of_Eritrea
