This hafted sago probe is made from metamorphic stone.  The tool was used to cut down sago trees for processing into starch in the West Sepik region of New Guinea.

The sago probe was collected by Ray Langford in 1971 in the West Sepik region of New Guinea, near Amanab/Imonda.  As a young man in the early 1970s, Ray worked for a mineral exploration company in the remote upper Sepik region of New Guinea.  This was not long after first European contact with the Indigenous inhabitants.   Recognising that their material culture was changing in response to new technologies, Ray acquired examples of their tools and other objects.  This was done through the barter system in exchange for tobacco, trade beads, red cloth, pocket knives and machetes, mirrors, and salt.

See the annotations for technological details about this stone tool.

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This tool is a cigar-shaped stone ipe sago probe hafted in an elbow-shaped handle.  The stone is metamorphic in origin and was shaped by pecking; the pits from this are clearly visible.  The stone was lightly ground after pecking.  The elbow-shaped handle was cut from the trunk and side branch of a small tree.  The short foot section served as the platform for firmly lashing on the two-piece clamp that secures the stone ipe.  The clamp was made by splitting a tapered piece of wood and hollowing out both halves to receive the stone.  Once the stone was lashed into the clamp, the clamp itself was lashed onto the handle’s foot.  This style of hafting is classified by the archaeologist Eleanor Crosby as Tradition 2, indirect hafting to a footed handle (variety T2.1, clamp attached to foot).

The lashing was expertly done with split cane using a complex braiding/weaving pattern.  The clamp is secured around the stone probe with a cylindrical braid slid up onto the large end, squeezing it shut.  A narrower cylindrical blade is at the top of the handle, perhaps to repair a crack in this area.  The cane used for the cylindrical braids is narrower in width and lighter in colour than the cane securing the clamp to the foot, perhaps indicating that they were made by two different craftspeople.  Unusually, braiding was also used to affix the clamp to the foot; clamp-hafted adzes in other parts of New Guinea are usually secured by a more simple form of cane lashing.  You can learn more about clamp-hafted adzes here.

The hafted tool is over a half-century old and has suffered damage from boring insects, but despite this, the lashing is exceptionally tight. The significant of the shallow geometric carving on the handle is unknown.  The engraving appears to have been done with a stone flake, cutting through the handle’s polished surface.  It is partly obscured by the lashing at the top end.  The handle is polished from use.

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Sago is the starch extracted from the crushed pith of the palm tree Metroxylon sagu (called sac sac in New Guinea pidgin).  Sago starch is nearly pure carbohydrate and supplied up to 85% of calories to traditional people around the Gulf of Papua and Fly River basin of New Guinea.  It was also a staple in the diet of people living in the Sepik River basin.  In northeastern New Guinea, where yam and taro played a major dietary role, Sago served as an alternative food source in times of scarcity.  Sago palm is endemic to New Guinea but was carried by people across Indonesia and Southeast Asia to Malaysia and eastward into the Pacific as far as Samoa.  Archaeological evidence of palm starch has been recovered from Pleistocene deposits in Niah Cave, Borneo, but the stone tools associated with starch extraction in New Guinea are from recent deposits or historical collections.  Sago remains an important food source across the region today.

Sago palm trees are planted as suckers in specially-managed sago gardens or swamps.  The trees take about 8-12 years to reach maturity and can attain heights of 10-12 metres before harvesting.  They are cut down just before flowering, when the starch content is highest, but before they put on seeds.  After harvesting, one of the tree’s suckers is allowed to become the main trunk.  Medicine was sometimes applied to the trunks to encourage growth and ensure plenty of starch content.  People in New Guinea recognised up to 15 different varieties of sago palm.

Sago harvesting was a collective task.  Men played a major role in identifying suitable trees and cutting them down.  Trees were tested by breaching the bark and sampling to pith; if too watery, the hole was patched to prevent beetle infestation, and a different tree was chosen.  Traditionally women were responsible for processing the trunk into sago starch, although in some areas they also cut down the trees.  Similarly, men sometimes did the sago processing.

The trees were cut down with a stone tool mounted in an adze handle.  In areas where sago was a key element of the diet, a special cigar-shaped stone with a bullet-shaped end was often used, called an ipe by the Heve people of the Wogamush River of the Sepik River basin.  The anthropologists Pierre and Anne-Marie Pétrequin refer to these tools as ‘sago probes’.

These cigar-shaped sago felling stones were about 15-20 cm long and 3.5 cm in diameter, and were made from metamorphic or igneous rock by hammer-dressing.  Sago probes were made in the recent past by Dani people at Darai village in the mountainous area of western New Guinea.  They collected igneous rocks from talus slopes in the foothills of the mountains and shaped them by pecking.  This was followed by grinding with the faces of the  hammerstone, using a sanding gesture.

The Heve people often obtained sago probes in trade from specialist manufacturers in the mountains to the south or in the Lake Sentani/Humboldt Bay region, and the Heve paid for them with cowrie and other shells.  Sometimes blunt-edged stone adzes were used to fell sago trees, or sharp stone adzes borrowed from the woodworking toolkit.  In historic times, stone felling tools were preferred to steel axes by some groups because the sharp steel tools tended to wedge into the pithy trunk.  The blunt-ended tool bruised and pulverised the plant tissue rather than cutting cleanly through it, and hence the tool was not prone to sticking in a cut.  Sometimes sago trunks were rafted along rivers and waterways to less swampy areas close to the villages for processing.  The cut logs could be submerged in water for prolonged periods, storing them for future processing.

To process sago starch, the area around the fallen trunk was first cleared of smaller spiny leaves and debris.  Next, large leaves were cut from the tree for shelters over the trunk processing area and to build the starch-washing infrastructure.  To begin processing, the bark at the base of the tree was split with the felling tool and peeled back for about a metre with sharpened stick wedges.  Sometimes the upper part of the bark was stripped lengthwise so that subsequent removal of the centre pith created a bark trough.  The bark trough from a previously-processed trunk was used as the primary element of the washing area in some regions.  The bark troughs were also used as canoes.

Sago pounding was traditionally done with a stone tool mounted in an elbow-shaped adze handle.  In some regions the pounding tool was similar to the cigar-shaped tree felling tool, but with a concave, or ‘dimpled’, working end.  Like the felling tool, these dimpled sago pounders were made by hammer-dressing metamorphic rocks, and were obtained in trade from specialist stoneworkers.  Sometimes a broken stone adze was recycled with the flat broken surface serving as the working end.

In the Kikori River basin of southeastern New Guinea, sago pounders called was were mounted with single-platform cores made of dark gray or black chert.  These cores measured about 5-13 cm long and 5-6 cm in diameter, and were flaked around the perimeter of the flat platform.  The final stages of manufacture often involved step-flaking similar to that seen on Australian horsehoof cores.  These sago pounding cores were pyramidal in shape and often elongated, and were hafted with the platform facing outward.  Similar core-based sago pounding tools—but made from basalt rather than chert—were called fiase by the Heve people and, like the ipe, they obtained them in trade from stoneworkers to the south.  Later in the 20th Century, the fiase/was stones in various regions were replaced by sections of steel pipe or other metal inserts.  Nevertheless, the chert core sago pounders were still in use—and made by specialist stoneworkers—by people in the Baina area (Kikori River) of southern New Guinea in the 2010s.  Sago pounders in Waira village on the Kikori River, interviewed in the 1970s, considered the steel tools inferior to stone for processing sago.

The sago worker (or workers) sat or stood at the side of the trunk, lifted the sago pounding tool above their head with both hands, and then chopped down forcefully so that the edge of the stone tool scraped a thin layer off the exposed end or face of the trunk and across the trunk’s grain, thus severing the longitudinal cellulose fibres.  It was conventional in New Guinea to hold and swing sago pounders—as well as hafted stone adzes generally—‘cross-handed’, with the dominant hand on the handle below the subordinate hand; this is the reverse of the conventional hand position used in the West.  The strokes were rhythmic and accompanied by a flick of the wrist at the end.  Special work songs were sung in time to the pounding to increase the starch yield.

A relatively steep cutting edge was desired for the stone tool’s scraping action, with the flat face oriented at about 80-90 degrees to the tool’s side.  The sago pounders were used extensively, causing rounding of the tool edge and the accretion of silica from the plant on the tool edge and surfaces.  The silica forms very bright, shiny gloss on the flat face of the tool, extending over the edge and part way down the tool face.  In the New Guinea stone toolkit, extensive silica gloss like this is only found on sago pounders.  Resharpening flakes with silica gloss on the dorsal surfaces have been recovered from archaeological excavations, but sago pounder resharpening is not often reported in the historical record.

As sago pounding proceeded, the minced shreds of the trunk piled up on the peeled-back bark of the tree, around the worker’s feet.  When the pile grew large enough, it was further pulverised with the flat face of the tool until it took on the consistency of coarse sawdust.  Periodically this minced sago was gathered into a bark or palm leaf bag and carried to the washing trough.  Washing troughs were built from the long bottom sections of the sago leaves or the trough-like section of sago bark described previously.  The trough was elevated at one end.  The sago mince was piled into the trough, water was poured in, and the mince was kneaded while the water flowed through it.  A hessian-like filter made from palm fibre was placed at the bottom end of the trough to hold back the cellulose mash.  The milky starch-saturated water flowed through the filter and into another trough or container for settling.  This was left to sit for an hour or two and the water was drained off.  The white glutinous starch chunks were then scooped into woven palm-leaf or bark bags and carried back to the village for drying in the sun.  After drying, sago starch was packed in leaf or bark packages and could be stored in the ground for up to two years.

The trunk was processed in sections of about 60-100 cm at a time, usually starting at the base and moving progressively up the trunk.  About three or four hours of pounding were necessary to fully process each section, and there were 6-8 of these sections per trunk.  Each section produced from 20-30 kg of starch, or enough food to feed a family of six for three days.  Between about 100 and 300 kg of starch could be obtained from one tree.  Sago starch was cooked in bamboo tubes or wrapped in leaves, often mixed with other ingredients to make it more nutritious—sago starch is very low in protein and vitamins and minerals.  Sago beetle grubs were also an important part of the diet, and these were encouraged to grow in the processed mash or in suckers planned for removal.  Mushrooms growing in discarded mash were also eaten, and the mash was sometimes fed to pigs.

Sago starch figured prominently in the famous hiri trade cycle established some 300-500 years ago by the Motu people of the Port Moresby region.  The Motu experienced a harsh dry season and sago could not be grown there, so they established long-distance trade (hiri lata) to obtain sago starch from villages on the Gulf of Papua to the west.  In late September or early October the men began preparing their ocean-going canoes with the iconic crab-claw sails, called lakatoi, while the women were engaged in moulding and firing thousands of their renowned earthenware pots to be exchanged for the starch.  The lakatoi consist of dugout canoe hulls joined by booms with a platform on top.  With the coming of the southeast trade winds in late October or November, the men set off to the west in trading fleets of about 20 vessels with the earthenware pots packed in dried banana leaves.  The traders stayed in the Gulf villages, rebuilding their lakatoi with additional hulls—expanding the canoes from 4-6 hulls to as many as 14 hulls—to carry back the sago.  They were carried home by the monsoon winds in January.  The return of the lakatoi was celebrated by dancing, singing, and feasting.

The volume of items traded in the hiri lata is staggering.  In 1885 a fleet of 20 lakatoi, crewed by 600 men, carried 30,000 pots on the outward journey, or about 1500 pots per canoe.  From 150 to 600 tons of sago were brought back on the return journey.  The processing of sago to meet this demand must have been almost industrial in scale, requiring the processing of between 495 to 1980 sago palms to meet the demand.  A minimum of 18 person days per tree was necessary for the sago pounding alone, which computes to at least 22-98 person years annually for the exported sago starch.  Given these labour requirements, and that it takes from 8-12 years for a tree to reach maturity, long-term cross-village planning and investment were required to sustainably manage the sago resource.  This attests to the value placed on the Motu pots as well as the esteem and lineal ties gained by these trading relationships.  The volume of sago processing consumed vast number of stone tools, and this may explain the development of specialist makers of the sago processing toolkits, particularly of the fiase/was variety of sago pounders favoured by people living on the Gulf.

Colonial authorities stopped the hiri trade cycle in the 1950s, but after New Guinea gained independence in 1975, the hiri trade began to be commemorated by the Hiri Moale Festival at Port Moresby.  Based on the traditional celebrations around the return of the lakatoi, this has become an important event in the modern New Guinea cultural calendar.