Composite arrows of Kalahari Desert

Materials World magazine
,
27 Nov 2019

Learn about the artistry of composite arrows made by the Ju|’hoansi San people of the Kalahari Desert, Southern Africa. 

The San people of Southern Africa are considered by many to be the most ancient race in the world. They are nomadic, egalitarian, hunter-gatherers, many of whom have maintained much of their traditional lifestyle, despite widespread marginalisation of their communities. Divided into three main nations, the !Kung, the Tuu and the Tshu-Khwe, as well as a plethora of sub-groups, this article will focus on the Ju|’hoansi San people. They are a southern !Kung group located in the Kalahari Desert in north-west Namibia, north-east Botswana, who comprise about 1,400 people living in 36 N!oresi (villages). The Ju|’hoansi are one of the few San groups who are still able to practice their hunter-gatherer lifestyle, although the breadth and freedom of their practices have been considerably limited by wider laws.

Tools of the people

The tools of the Ju|’hoansi can be divided into three broad categories – those used for gathering, for general everyday, and hunting tools. Gathering cloaks, called Kaross, 

are typically made from animal skins originating from large antelopes, such as eland or kudu. Sharpened wooden tools, or combined wood-iron tools, are used to dig for foods and useful materials, while general tools may include fire-hardened woods to create a pestle and mortar, quivers made of fire-hardened hollowed tree roots, and male-female sticks for starting fires. The Ju|’hoansi hunting tools – bow and arrows, and spears – are perhaps the most technically significant, exhibiting careful and well-planned engineering designs.

Materials and manufacture

The Ju|’hoansi have invested time and effort into developing the composites and adhesives that lead to the production of each arrow. So much so that each stage of manufacturing is critical for a successful final product, which typically takes three days from start to finish. The process is naturally slow since there are curing times for adhesives and speciality methods of preparing arrowhead parts, and each procedure is completed by hand. Some of their arrowheads are made of root of Rhus tenuinervis, giraffe shinbone and ductile iron, introduced during the German occupation of 1884, each of which is inserted into a hollow reed of Phragmites sp. With the exception of the arrowheads, the majority of other materials used to construct arrows are common to them all. This includes the reed forming both the shaft and the link shaft, which consists of a thinner reed connecting the bone-to-bone and metal-to-bone in the bone and metal-tip arrows. Also included are two separate types of glue, one of which is viscous amber sap from the trunk of the tree Terminalia sericea, while the other is a composite comprising milky latex exude from the roots of the Ozoroa schinzii bush, mixed with the fine black ash of freshly burnt Aristida adscensionis grass. Giraffe and kudu achilles’ tendons are also used in the making of these arrows, and each arrowhead is finally tipped with a deadly poison, usually extracted from the grub of Chrysomelid beetles, Diamphidia sp. and Polyclada sp. These grubs are typically dug out from the base of Commiphora sp. or Sclerocarya birrea trees, at about a third of a metre below the surface of the ground.

It is generally understood that the chronological order of materials used to construct arrowheads began with the root, which was followed by bone, and ended with ductile iron. Nevertheless, all three arrowhead types are still in use by the Ju|’hoansi, with the root being preferred for the close-range hunting of small prey, while the bone and metal arrowheads are used to hunt larger prey at longer ranges.

Arrow design

Ju|’hoansi arrows are, for the most part, composites made of natural materials, and reeds form the main shaft in all arrow types. The cellulose fibres of these reeds grow unidirectionally along the reed length, meaning they have high stiffness and strength along their lengths but are weak in their transverse directions. Since the arrowheads are wider than the reeds, and are inserted and firmly fixed into them, a failure will occur in the reeds between the fibres through forced transverse contact with the arrowhead.

To circumvent this problem, the Ju|’hoansi reinforce the portion of the reed that will bear the transverse forces by first wetting the carbonised black Ozoroa schinzii glue and then applying it to the surface of the region. Following this, they tear thin strips, about 0.5mm-thick by 1-2mm-wide, of water-saturated giraffe tendon, which they wind around the reed over the surface of the glue. They conduct the same procedure for the reed link shaft observed in the bone-tip and metal-tip arrowheads. Once dried, the glue fixes the tendon tightly to the surface of the reed shaft or link shaft, and the tail end of the arrowhead is covered in Terminalia sericea glue, after which it is inserted firmly into the reed. In the cases of the bone-tip and metal-tip arrowheads, the same procedure takes place with the appropriate ends of the arrowhead parts being glued and inserted into the reed link shaft as well. 

The Ju|’hoansi counterweight their arrowheads from root to tip to decrease tilting problems when they are fired. In the case of root-tip arrows, loss of material towards the tip of the arrowhead is balanced by preserving a thick section of the root at the shaft-end of the arrowhead. The procedure is more complicated for the bone-tip and metal-tip arrowheads, as the counterweights are essentially large pieces of giraffe shinbone with more bulbous geometries than the arrowhead tips.

These counterweights are chaffered down at the ends so they can fit into the reed shaft and the reed link shaft. The tips of these types of arrows are more finely constructed, both being long and thin in comparison to the bulbous counterweights.

Wet giraffe shinbone-based tips are made by cutting and grinding, while ductile iron is heated over coals and hammered, cut and ground into shape. The Ju|’hoansi typically use metal iron fencing they find in their localities. The geometries of the arrowhead tips widely vary which is understood to relate to the density of the material used to make the tip. The root tips, which are the largest, are the lowest density at 0.9g per cubic centimetre (g/cc). While the smaller bone tips are 2.0g/cc, the ductile iron tips have a 7.6g/cc density, and are geometrically the smallest of the three types. This indicates that the Ju|’hoansi arrows are geometrically designed and manufactured, as a response to their material and physical properties.

We may further note that there is a design logic in how the reed link shaft is used. It would not, for example, be any more time-consuming to create a single part arrowhead in the bone-tip and metal-tip arrows, in similitude to the root-tip arrow. Yet, the Ju|’hoansi preferentially design these in three separate parts, the central piece being a composite joint made of giraffe tendon-reinforced reed.

Following discussions with the elders of a Ju|’hoansi family, the research team understood that these were in fact purposely made to break. Whereas a root arrow is a short-range projectile that can easily be recovered, the bone and metal-tip arrows are used for long-range and can be easily lost, either in a distant hunting ground or while attached to a fleeing animal.

Arrows are vital tools for hunting and their reuse and recyclability can save precious time and natural resources. As such, the Ju|’hoansi design the arrow-tips of the bone and metal arrows in such a way that they will break off after impacting and penetrating an animal. Animals such as giraffes or elands are large and the poison takes time to spread. While the Ju|’hoansi track their kill – which may take up to three days for large, strong mammals – they can retrieve the majority of the rest of their arrow, which will typically break off at the reed link shaft where the hunt took place. This allows them the opportunity to reuse much of the arrow, only having to replace the reed link shaft and the tip, should the tip not be found with the dead animal.

Hitting home

The Ju|’hoansi San are living models of humanity’s history, yet very little is known about the design parameters they have manipulated to satisfy the specific functional requirements of their hunting tools. Their arrows are exemplars of function-specific engineering and design, and are manufactured using simplistic tools, made primarily of natural materials sourced from the local environment. They have been designed to be balanced in flight, lightweight and aerodynamic, recoverable and reusable, and to be damage tolerant.

The Ju|’hoansi are the composite arrow master crafters of the Kalahari, and have developed their technologies over 200,000 years of trial and error. Today, the San people’s hunter-gatherer lifestyle is under threat. They have been marginalised to the extent that many San groups now accept handouts of game that has been hunted by foreigners. Anthropologists predict the San way of life has less than 25 years before it ceases to exist.


Parvez Alam FIMMM is University of Edinburgh School of Engineering Senior Lecturer.