Everyone is familiar with the bow and arrow, but what on earth is an atlatl? Although this implement was once used all over the world and was an important part of life, in most areas it was replaced by other weapons so long ago that it is no longer remembered, and most people today have never even seen one. In a few areas, like Mesoamerica and Australia, use of the atlatl continued up to (and beyond) European contact, but throughout most of the world it is known today only from archaeological specimens and reconstructions by interested hobbyists, who are often archers. One interesting aspect of the study of the atlatl in American archaeology has been the important role played by these amateurs, who have often demonstrated through experiments that the conclusions of archaeologists about the use of atlatls were clearly mistaken.
An atlatl is basically a device for assisting in throwing a spear. They are almost always made of wood, which means that archaeologically they rarely survive intact except in very dry areas like the Southwest. They are typically about half a meter long, and take the form of a long, thin board with a shallow groove running down the middle and a hook or spur at one end to hold the butt end of the spear. Southwestern examples typically have leather finger loops at the point where the atlatl would be held. Occasional examples in other areas, as well as the presence of associated artifacts made of more durable materials, have demonstrated the use of the atlatl throughout the Americas, but understandings of how these atlatls were made and how they functioned have been heavily reliant on Southwestern examples, particularly the exceptionally well-preserved ones found in Basketmaker II rockshelters in the Kayenta area by Alfred Kidder and Samuel Guernsey in the early twentieth century. There is also a considerable amount of ethnohistoric data on the use of the atlatl in Mesoamerica, which is helpful in understanding atlatls elsewhere but must be used cautiously because Mesoamerican atlatls are typically rather different in form from Southwestern ones, and there may have been corresponding functional differences as well.
The precise way the atlatl functioned has not always been apparent to archaeologists, who have in general been notably disinclined to experiment, and amateur experimenters using replicas of archaeological atlatls have made important contributions to understanding this. One such amateur was Calvin D. Howard of Houston, who published a useful paper in American Antiquity in 1974 reporting on his experiments and explaining how an atlatl actually works. Here is his basic point:
Surprisingly, considering popular consensus, the atlatl is not a catapult or “flipping” device. In fact, during a proper throw, the spur at the aft end of the atlatl reaches no greater elevation than that reached by the handle at the forward end. The spur does not swing upward in an arc, but merely “follows through” in the original portion of the spear’s flight path. Therefore, the most expeditious way to learn the use of the atlatl is to throw the spear with the atlatl exactly the way it is thrown without it.
The atlatl provides greater thrust than the unaided hand simply because it remains in contact with the spear during a greater portion of the total thrust than does the hand.
He later elaborates on this:
When a spear is thrown with the atlatl, the thrust begins with the hand at the same location behind the thrower, that is, as far back as his reach allows. The hand is moved forward along the same necessary straight path toward the target. When the arm nears the outstretched position-the point of release for the hand-held spear-the atlatl is still in contact with the spear. As the hand and the forward end of the atlatl begin the downward curve, the aft end, with the spur still in contact with the spear, continues on the straight thrust line. The atlatl is therefore converting downward curving thrust to straight forward thrust, thereby prolonging contact between spear and thrust. The spear thus receives a greater portion of the total thrust energy expended.
I haven’t used an atlatl myself, so I just have to trust Howard on this. He also argues, based on his own experiments, that longer spears are more affected by the increase in thrust given by the atlatl relative to a bare-handed throw, and that the increase in thrust due to the atlatl is about 60%, which makes it a very useful device indeed. He also says that his experiments have shown that atlatl “weights,” stone objects found lashed to most Southwestern archaeological atlatls but unknown in Mesoamerican examples, provide no additional benefit in terms of thrust, and in fact reduce the effectiveness of the atlatl. The function of these “weights” has been one of the most puzzling issues in the study of atlatls, and I’ll address it in more detail later.
Howard, C. (1974). The Atlatl: Function and Performance American Antiquity, 39 (1) DOI: 10.2307/279223
You haven’t lived, till you’ve seen Atlatl Bob!
http://www.atlatl.com/atlatlvideo.php