Archaeologists believe that Native American hunters began using the bow and arrow relatively recently, that is, around 1200 years ago. While 1200 years ago may seem like a very long time, consider that there have been people living on the North American continent for at least 13,500 years. At about 1200 years ago, the atlatl (a sort of spear-throwing stick) was replaced by the bow and arrow. This weapon gave hunters even more accuracy, distance, and speed in their shots. It also allowed hunters to be more secretive. They could move up on and shoot their prey while crouching behind a bush or from within a prairie of tall grass. This was a clear advantage over the old-style hunting method: hunters using an atlatl could hurl a dart or spear only when they were standing erect, revealing their position to an easily spooked herd of deer. Hunters could also carry many more arrows than darts on their hunting trips.
Bow and arrows differed in size and shape, as well as the materials used to construct them. Early bows were often 1.0 � 2.0m in length�taller than a man, in some cases! After Spanish explorers brought horses into the New World and Native Americans began hunting on horseback, shorter bows were developed for ease of handling. The mounted hunters and warriors were skilled with their weapons, whether hunting buffalo or engaged in battle. Texas Ranger Noah Smithwick recalled that Lipan Apache Indians could shoot a dozen arrows in the time that it took for a man to load a muzzle-loading gun.
http://en.wikipedia.org/wiki/Atlatl
http://www.deepcreektimes.com/kids/november200 3.html