Stone Tools on Flores, Indonesia


Dr Mark Moore

Australian Research Council Fellow

Archaeology and Palaeoanthropology

University of New England

Armidale, New South Wales, Australia


Research in Indonesia has shown that early hominins settled the region by about 1.6 million years ago and were present in the Soa Basin on the island of Flores by 1.0 million years ago (Brumm et al. 2010).  The hominin species responsible for making the earliest stone tools on Flores is presently unidentified although it was presumably the ancestor of the hominin Homo floresiensis, discovered in 2003 at Liang Bua Cave about 50 km to the west (Morwood et al. 2004; Brown et al. 2004).  Present understanding of the cave deposits suggests that H. floresiensis made stone tools at Liang Bua from about 95,000 years ago to perhaps as recently as 17,000 years ago (Moore et al. 2009; Westaway et al. 2009); thus non-modern hominins practiced a stoneworking tradition on the island that lasted over 900,000 years.


Our joint Australian/Indonesian research team has analysed the early stone tools from two important sites in the Soa Basin—Wolo Sege (about 1.0 million years old [Brumm et al. 2010]) and Mata Menge (about 840,000 years old [Morwood et al. 1999]).  These early stoneworkers made tools by striking flakes from volcanic stones they found in riverbeds and lakeshore cobble deposits.  Flakes were struck from two faces of these stones, creating irregular but roughly round or ovoid cores with a sharp edge around all or part of the periphery.  Sometimes the cores would be held in such a way that the flake would run down this sharp edge, what archaeologists call a 'burin' technique.  Other times the flake blank or core was placed flat or edge-on onto a stone anvil and broken by smashing it with a hammerstone.  The stoneworkers often reduced large flakes in the same way that they reduced cobbles.  Flakes were sometimes flaked more intensively on two parallel edges, creating an awl-like projection—objects archaeologists call 'perforators' (Brumm et al. 2009). 


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Stone 'perforators' (left) and sharp-edge 'radial coreŇ (right).  The examples in the top row are from Mata Menge and the bottom row are from Liang Bua.  Scale 50 mm.  

(copyright Mark Moore 2004)


perforator radial core

This video shows in 3D a ‘perforator’ made by H. floresiensis at Liang Bua.

(copyright Mark Moore 2009)


This video shows in 3D a ‘radial core’ made by H. floresiensis at Liang Bua. (copyright Mark Moore 2009)





Our analyses of these stone tools showed that H. floresiensis at Liang Bua flaked stones in identical ways to their ancestors at Mata Menge, producing the same sorts of cores, flakes, and tools (Brumm et al. 2006; Culotta 2006).  H. floresiensis stoneworkers flaked large rounded cobbles and boulders of volcanic tuff available in a riverbed several hundred metres from the cave.  The cores flaked by H. floresiensis inside the cave were made on large flakes struck from these cobbles and boulders, so it would appear these little hominins preferred to carry with them relatively small, light-weight tools rather than cobble cores (Moore et al. 2009). 



Examples of stone tools from Liang Bua Cave, Flores.  Scale bars10 mm.

(copyright Mark Moore 2009)


The species ancestral to Homo floresiensis is still debated, but some researchers think that the Flores hominin descended from an early African Homo species such as Homo erectus.  If so, the hominin's ancestor may have left Africa up to 1.8 million years ago.  When we compared the Flores stone tools the early African ones of about that age, we found a remarkable degree of similarity between them, right down to the production of perforator-like tools (Moore and Brumm 2009). 



Similar stone tools from Liang Bua, Mata Menge, and Olduvai Gorge, Africa (after Leakey 1971), arranged chronologically.

(copyright Mark Moore 2009)


The tools from Mata Menge and Liang Bua, like the early African ones, demonstrate early hominin's considerable skill at striking flakes.  Yet, in cognitive terms, Flores stoneworking was not terribly sophisticated:  the tools were amorphous and undifferentiated (Moore 2007, 2009).  The perforators may be an exception to this, but we may be projecting our modern sensibilities when we sort these tools out for special emphasis.  It appears that H. floresiensis focused on producing sharp cutting edges and not 'aimed-at' tool forms in our modern sense. 


The common approach to stoneworking in the Soa Basin and Liang Bua demonstrates a remarkable period of technological uniformity on Flores, a uniformity that stretches back to the earlier sites in Africa.  Stone tools were clearly a crucial part of the early hominin's adaptation to the environment.  Yet palaeoanthropologists have shown that natural selection on Flores caused the H. floresiensis body to morph in variety of surprising ways, so the technological adaptation alone was not sufficient to prevent this.  This is a timely reminder given the technological obsessions of our modern culture.


So how did stone flaking by modern H. sapiens at Liang Bua compare to stone flaking by H. floresiensis?  The stone tool debris left by modern humans in the cave—dated to after ca. 11,000 years ago—differed in several ways.  First, modern humans preferred to flake chert rather than the volcanic tuff preferred by H. floresiensis.  Second, modern humans used stone tools differently.  For instance, silica gloss deposited on some of the modern human tools indicates that they were used in processing plant materials, perhaps for mat-weaving or basketry.  And third, modern humans used fire much more than H. floresiensis.  A large proportion of their stone tools are burned, probably from accidentally scuffing them into hearths or cooking ovens inside the cave (Moore et al. 2009). 


Stone types preferred by H. floresiensis (left) and H. sapiens (right) at Liang Bua.


Yet, despite these clear differences, we were surprised to discover that modern humans at Liang Bua made their tools in the same ways as H. floresiensis (Moore et al. 2009; cf. Culotta 2009).  H. floresiensis and modern humans reduced larger flakes that they brought to the cave and used the same flaking techniques to do so, creating stone products and byproducts of remarkably similar size and shape. 


Comparison of stone tools made by H. floresiensis and modern H. sapiens at Liang Bua.  The uncircled specimens were made by H. floresiensis. 

(copyright Mark Moore 2009).


About 7000 years after the initial occupation of the cave by modern humans we see the appearance of more complex stone tools.  These were rectangular chert adzes chipped to shape using a punch and then ground to a cutting edge on one end.  Despite this innovation, the modern human occupants also flaked stones using the simpler methods until the relatively recent past. 


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Chert adze blank made by modern H. sapiens near Liang Bua.

(copyright Mark Moore 2005)


How might we explain the similarities in stoneworking between H. floresiensis and modern humans?  One possibility is that the technology reflects such simple 'basic skills' of stone working that humans converged onto it as they migrated through Southeast Asia (cf. Moore and Brumm 2007).


Our ongoing research on Flores and elsewhere in Australasia continues to explore the interplay between hominin species, cognition, and the intricacies of stone flaking.  This is a profound story, one that goes to the heart of our specie's evolution and the technological niche we occupy.




Chronological summary of hominin species and their stone tools on Flores.

(copyright Mark Moore 2009)