In my recent entry on the atlatl and dart, I speculated about the reason why its use faded away, and was largely supplanted by the bow and arrow. I wrote:
In fact, darts thrown by atlatls are so effective that it is interesting to speculate about why that technique was largely supplanted by the use of the bow and arrow. I suspect that it may have something to do with the declining size of prey animals. As mammoths and mastodons and the other giant megafauna became extinct, hunters had to turn to smaller, lighter prey, and it may be that the heavy firepower of an atlatl was no longer necessary.
And I think that there may be some merit to that idea. Recently, however, I received correspondence from Dr. Karl Hutchings, whose work on lithic fractures in stone points has provided strong evidence that atlatls were used by the first people to enter the Americas, even though no direct evidence of atlatl use from that time has yet been found.
In his letter to me, Dr. Hutchings has postulated some alternate (or additional) theories about why the bow and arrow so largely supplanted the atlatl. With his permission, I quote at length:
I also read with interest your thoughts concerning the persistence of the atlatl vs. the acceptance of bow technology. My own thoughts on the matter are a bit different. It may be noteworthy that recent users of the atlatl hunted small game with it. For example, Australian Aborigines hunted small game (e.g., reptiles) with the atlatl (they call it a Woomera of course), and ducks were being hunted with the atlatl up until the 1960s in Mexico. So I don’t think game size per se is necessarily the key factor, though it may figure into it. Instead, I expect that the nature of the terrain (i.e., open vs. forested; rocky vs. “cushioned” [for want of a better word]) and the relative level of human aggression were important factors.
The atlatl makes sense in open terrain where the arm motion is unrestricted, and where a long-distance, arcing trajectory is unimpeded. Under such conditions it would be especially beneficial for hunting herd animals. But it would be effective in some other conditions as well.
The atlatl is quite effective at close range for hunting small game, but can be hampered by the nature of the “ground cover”. In rocky terrain, one can expect a lot of broken darts regardless whether one hits the small game target, or misses entirely – in either case, the dart is going to hit the ground, since even if the target is hit, the dart will likely continue through it. I suspect that the atlatl is not preferred in such rocky environments, but on soft (e.g., humic, marshy, sandy, or even water) terrain (like the Australian and Mexican examples), this would not be a problem. In contrast, archers may not have experienced as significant a problem in rocky terrain due to the flatter trajectory (i.e., increased inherent accuracy), and reduced “cost” of arrows (relative to much larger darts).
The other likely factor is the relative level of human aggression. The bow is, to a great extent, a weapon of warfare due to the low cost of projectiles, the ability to carry very large quantities of projectiles, and the ability to shoot from positions of cover. So, in those areas where the bow was adopted due to interpersonal aggression, it may make sense to abandon the atlatl, and simply use the bow as a dual purpose weapon.
Of course, the reasons for preferring one vs. the other are likely even more complex than this, and undoubtedly incorporate concerns of economy, ethnicity, aesthetics, and more.
Just my speculations on the issue.
Dr. Hutchings’s comments highlight several aspects of my fascination with the Pleistocene period in North America.
First, Dr. Hutching’s ideas all make sense to me, and I had not considered any of them.
Second, I still think that there is merit to notion that these exceptionally skilled hunters may have adapted a lighter technology to lighter game, as the megafauna disappeared. Why continue to use heavy artillery, as it were, for lighter prey? Of course, the atlatl/dart technology could have been (and was) adapted for use on smaller animals, Dr. Hutchings noted above. Still, I think that at some point, as the darts shrank, it became just as effective and easy to use bows and arrows. This ties in with a point that Hutchings makes above – there is a lower cost to make and replace arrows than darts.
Another question is why, after bow and arrow technology was adopted, the atlatl/dart system was apparently no longer used even in against large animals in the open, grassy country that, as Hutchings notes, is optimal for it. I am thinking here about hunting bison or elk on grassland. I understand that the Paleo-Indians at this time had to hunt on foot, and it may be that they could stalk prey more effectively and make better use of cover with a bow, rather than an atlatl, which requires the highly visible standing, throwing motion. Nonetheless, large animals on open terrain remained, but for some reason, the technology shifted from atlatls to bow. Why?
Of course, one additional piece of information that might shed some light on this issue is the pattern of settlement/exploration of the continent by the first people here. What did they preferentially hunt? And where, i.e. in what type of terrain? Perhaps as the megafauna disappeared, the Paleo-Indians had to shift to hunting different game, in different terrain, and the change in terrain drove this shift in technology.
Ultimately, I suspect that there is no single explanation of this technological shift. Scarcity of good stone may have influenced knappers to make more, but smaller points – who knows?
My point here is, the fact that we know so little about life in the Americas thirteen or so thousand years ago is the very reason that it is so fascinating to me, and why I applaud creative scholars like Dr. Hutching who are doing such interesting work.
 “Atlatl and Dart,” February 19, 2015.
 Indeed, his work formed much of the basis for the “Atlatl and Dart” entry.
 Correspondence of February 25, 2015, from W. Karl Hutchings, Ph.D., Assistant Professor, Anthropology (Archaeology), Thompson Rivers University, Kamloops, BC V2C 5N3.