1. Homo ergaster in Africa
The First Colonists: Expansion of Hominim Range

2. Distribution and Nomenclature
● The designation of Homo ergaster is
relatively recent, and is intended to
distinguish the early forms of Homo
erectus from the later forms
● This has met with some resistance from
specialists, for those that are opposed to
this distinction see no justification for
positing a different species
● Irrespective of the controversies
amongst the palaeoanthropologists,
there is evidence of a change in the
anatomy and behaviour in the species
that is considered by some as Homo
ergaster
● Our earliest finds derive from East
Africa, sometimes at the sites where
Homo habilis was found in older layers
● It is clear that Homo ergaster/Homo
erectus was an extremely successful
species and was the first to colonise
regions outside of Africa

3. Affixing the Age of Homo ergaster
● Nevertheless, in this lecture we shall
consider the evidence only from East
Africa, where this species presumably
diversified from Homo habilis and explore
the later diffusion inside Africa and into
Asia in the following lecture
● The paucity of sites affording remains of
Homo ergaster renders it difficult to
determine the age range of this species
● It is, however, commonly thought to have
flourished between 2.0 million and 1.6
million years ago
● Some have suggested that it is
significantly younger, emerging only at
1.7 million years
● The dates from the site of Dmanisi in
Georgia have affixed the occupation by
Homo ergaster here to 1.88 million years,
so presumably it must be older in Africa

4. Physical Characteristics
● No agreement exists on which features
distinguish Homo ergaster from Homo
erectus
● This renders the determination of this
species rather arbitrary; hence the
controversy regarding its status
● An enlargement of cranial capacity and a
slightly smaller set of teeth does, however,
distinguish Homo ergaster and early forms
of Homo erectus from Homo habilis
● It is widely accepted that this form of
hominim evolved out of Homo habilis,
although there are some that select Homo
rudolfensis as a probable direct ancestor
● We are able to study the inter-relationship of
cultural behaviour and evolution with this
species (and Homo erectus) better than with
any other preceding hominim form because
of the larger data-set but also the expansion
of the range of settlement which implies
certain social and technological features of
culture

5. Cranial Capacity
● Homo ergaster shows an increase in
cranial capacity (700-900 cm3) from that
of Homo habilis
● The skull bones are thinner and lack an
obvious depression, or sulcus, on the
surface, which may be the most-
distinguishing characteristic between
Homo ergaster and Homo erectus skulls
● Also, the face of Homo ergaster is less
robust (more gracile) than is that of Homo
erectus
● Homo ergaster skulls also display
increased cranial breadth across the
parietal bones, as well as an increase in
the length of the occipital bone
● A broadening in the nasal bones and
nasal openings also can be seen
● Homo ergaster skulls also show a shorter
cranial base and greater development of
the mandibular symphysis

7. Dentition and Diet
● The dentition of Homo ergaster is
similar to that of Homo sapiens, but
the teeth of the former were slightly
larger to that of the latter
● However, Homo ergaster shows
some dental reduction when
compared to earlier Homo species
● The interesting feature of Homo
ergaster teeth is located on the
backside of the incisors
● These teeth are ‘scooped’ in
appearance and referred to as
‘shovel-shaped'
● Some scholars have suggested that
such teeth constitute an adaptation
for hunter-gatherers to process food,
and this is indeed a distinguishing
characteristic of the Native
American populations

8. Locomotion and Stature
● It is indisputable that Homo ergaster
was fully bipedal—the pelvis, joints
and vertebral column demonstrate this
● This species was slightly taller than
Homo habilis, but the small fossil
sample renders it difficult to make any
statements regarding diversity in size
● Altogether, the species is more gracile
and was probably faster than Homo
habilis
● The long arms of Homo habilis have
vanished, and there is more
proportion in the body, possibly a
result of evolutionary adaptations
associated with full bipedalism and
also a greater endurance for long-
range movement
● Rather than having the ability to run
quickly, Homo ergaster seems better
suited for walking long distances

9. Social Structure and Behaviour
● We can be certain that Homo ergaster was
capable of producing fire, for this was a
necessity in their expansion within and
beyond Africa
● This undoubtedly began to accelerate the
transformation of dentition, the digestive
tract, and the range of foods that could be
consumed
● Moreover, it may have also permitted a
more developed social structure focusing
on the hearth and the communal sharing
and preparation of food
● Expansion of range also suggests slightly
larger population numbers, perhaps even
an adaptive advantage over Homo habilis
in that this species never appeared to have
colonised new territories
● A question of climatic change, too, is also
relevant to the triggers for Homo ergaster
expansion, but it is probable that social
structure, technological innovation, and
dietary flexibility were essential for the
expansion to have been successful

10. Lithic Industry
● After roughly 1.6 million years, a new lithic
industry emerges in Africa known as the
Acheulean
● This refers to a tool-kit based on the
production of bifacially manufactured
handaxes
● Although a relatively simple type of tool to
produce, it was highly practical and was
distributed throughout the Old World and
persisted until at least the end of the
Middle Palaeolithic (ca. 35,000 BP)
● Its production implies a good grasp of
causality, but also a sense of symmetry
that can possibly be explained with
reference to the development of
mechanisms coordinating the function of
the two sides of the brain, namely, a
change in the frontal cortex
● This industry completely supplants the
chopper industry in Africa, but the chopper
industry continues to flourish elsewhere—
in East Asia, handaxes do not occur at all

12. The Expansion of the Genus Homo
Movement in Africa and Onward to Asia

13. Dispersal of Homo
● The diffusion of the genus Homo appears to have begun rapidly after its
emergence
● We have encountered evidence of Homo ergaster occupation at Dmanisi, in
Georgia, already at between 1.88 million and 1.6 million years the former is the
more likely date)
● Some suggestions of even earlier occupation in the Middle East, most particularly
in Israel, have been adduced that would place this at roughly 2.0 million years
● Other studies at Riwat in Pakistan, and in China, have also provided early dates
that situate the presence of Homo between 2.4 and 1.6 million years
● The earliest dates here, however, are profoundly controversial but it is difficult to
dismiss them entirely on a priori grounds
● Although there is a relative increase in sites at 1.6 million years, this should not
lead us to accept these dates as more reliable than the older sites in Eurasia and
outside of East Africa
● It is clear that the Dmanisi and Trinil site (in Java) are likely older by at least
100,000 to 200,000 years
● Moreover, they are all based on choppers rather than the Achelean tradition which
is consistent with early dates for dispersal

15. Dispersal in Africa
● We must also bear in mind that the
diffusion of Homo occurred within
Africa, as well as beyond Africa
● This must have occurred before the
occupation at Dmanisi and elsewhere,
at least for the north-east portions of
the continent
● Almost nothing is, however, known
about the expansion of Homo into
Egypt and the dating of the putatively
early sites in north-west Africa are
wrapped in controversy
● Only an handful of sites older than a
million years are known in the north of
Africa
● Some debate also concerns the type
of hominim that produced the African
tools—the absence of fossil remains
leaves this an unresolvable problem

16. Mechanisms of Expansion
● A perplexing problem concerns the
mechanism of population expansion out of
East Africa
● Numerous possibilities have been adduced:
1. Population rise
2. Reduction of available resources
3. Expansion of social territory
4. Wanderlust
● All of these are difficult, if not impossible, to
prove or falsify through the archaeological
record
● It is difficult to imagine a rise in population
sufficient to compel population to move, but
perhaps the answer lies in the perceived
need for space
● The mechanism may have been access to
better habitats, leading to expansion

17. Technology and Fire
● A possible explanation for the gradual diffusion
of Homo is an advance in technological facility
or an improvement of the environmental
conditions which might have favoured
colonisation
● Perhaps the most significant innovation that
could have facilitated the expansion of
population is the discovery of fire
● This would have permitted settlement in
regions that would have been difficult and
otherwise dangerous for Homo and was most
certainly involved in the expansion to more
temperate regions such as Georgia, Pakistan,
China and also North Africa
● Less obvious are the advantages that might
have been provided by the emergent
Acheulean industry and other aspects of
material culture
● It must, however, be considered that fire might
have made spear tips harder and also
permitted the consumption of foods that might
otherwise have posed a digestive problem

18. Middle Eastern Possibilities
● The passage to Dmanisi must have
been over the Middle East, but we do
not have any reliable dates from sites in
this region that place the expansion of
Homo to roughly 2.0 – 1.6 million years
● Many sites affording chopper tools and
Acheulean hand-axes have been
nominated as potentially being from this
time frame, but only Ubeidiya in the
Jordan Valley of Israel has provided
wholly reliable dates of being between
1.6 million and 1.4 million years
● Although obviously an important site, it
is later than those known from Dmanisi
and also Trinil in Java
● We cannot, therefore, adduce any
evidence from the Middle East or, for
that matter, North East Africa
contemporary with the expansion of
Homo

19. Dmanisi, Georgia
● Perhaps the most spectacular discovery
from the Lower Palaeolithic has been
the recovery of human remains and
tools at the site of Dmanisi
● The dating of this site reliably places it
between 1.88 and 1.6 million years,
most authorities favouring the former as
being likeliest
● This provided unequivocal evidence of
early Homo migration into Eurasia,
although there were numerous
suggestions that this indeed occurred
from the Chinese and Java specimens,
although there has been persistent
concern over the reliability of the dates
of these
● The hominim remains here have been
assigned to Homo ergaster, but in the
tradition of many of the taxonomic
debates, some have called it Homo
georgicus

20. The Hominim Remains
● The hominim remains from Dmanisi have
been regarded as belonging to Homo
ergaster or Homo erectus, but the difficulties
of distinguishing amongst the early Homo
species is illustrated by some declaring these
remains to represent Homo habilis
● It is clear that these are early Homo remains,
which is why the designation of Homo
ergaster was made
● If we regard Homo ergaster as an archaic
form of Homo erectus, this is perfectly
consistent with the dates and the process of
expansion outwith Africa suggested by these
● It is, furthermore, consistent with the evidence
from East Asia which all represent archaic
forms of Homo erectus
● An absence of any specimens from Homo
habilis in Asia, and indeed outside of East
Africa, militates against this species
beginning the colonisation process

22. Lithic Industry
● The lithic industry from Dmanisi is
fascinating, as it consists entirely of a
chopper based tradition cognate to the
Oldowan tradition
● This suggests that the migration out of
Africa occurred before the advent of the
Acheulean tradition, which seems to have
emerged at roughly 1.6 million years
● It is relatively primitive but clearly belongs
to the Developed Oldowan industries
encountered in East Africa
● We cannot postulate that this industry
was pursued because of a lack of raw
material suitable for the production of the
hand-axes as it is no worse than material
available at places such as Olduvai
Gorge
● It is similar to the industries encountered
elsewhere in Asia from this broad period
and might reflect an insularity of the
migrant population

23. Reduction Strategies
● The choppers represent the most basic
reduction strategy—basic, but highly
efficient
● Flakes were struck from the pebbles,
creating sharp edges suitable for
chopping or cutting material
● The flakes themselves were likely utilised
as tools also but the antiquity of these
specimens and there exposure to
weathering in some of the deposits
renders it impossible to apply micro-wear
analysis on them to determine function
● Much ink was been spilt on discussions
concerning what the reduction strategies
imply about cognitive ability
● It is clear that they reflect a sense of
symmetry, which is sometimes associated
with the development of distinct activities
in the different brain hemispheres

24. Symmetry and Cognition
● In addition to the symmetry, which involves an
immense amount of motor co-ordination not
seen in the implements produced by
chimpanzees, there was an appreciation of
causality manifested in the striking of different
types of flake at different points in the reduction
process
● Both fast and slow percussion were used,
along with different force, to detach different
types of flake to give the cores their distinctive
symmetric shape
● This is not an innovation of Homo
erectus/Homo ergaster, as a similar capacity is
demonstrated in the industries of Homo habilis
● It nevertheless signals an advance in cognitive
capacity that is clearly distinct from that seen in
the earlier phases
● How much of this is cultural knowledge, and
how much actually a change in brain
structure ?

25. Ain Hanech, Algeria
● A site that is roughly contemporary
with Dmanisi, but in northern Africa, is
Ain Hanech
● The dating of this site is disputed, but
some have situated it at roughly 1.9 to
1.7 million years
● It affords tools produced in the
chopper tradition, which is again
consistent with the migration of a
population out of East Africa before
the emergence of the Acheulean
tradition
● The colonisation of North Africa would
have involved the crossing of many
different types of ecological zones,
namely, jungle, desert and—most
significantly—mountains
● Remains of equus have been
recovered in association with the finds
here